Biology Explainer: The big 4 building blocks of life–carbohydrates, fats, proteins, and nucleic acids

The short version
  • The four basic categories of molecules for building life are carbohydrates, lipids, proteins, and nucleic acids.
  • Carbohydrates serve many purposes, from energy to structure to chemical communication, as monomers or polymers.
  • Lipids, which are hydrophobic, also have different purposes, including energy storage, structure, and signaling.
  • Proteins, made of amino acids in up to four structural levels, are involved in just about every process of life.                                                                                                      
  • The nucleic acids DNA and RNA consist of four nucleotide building blocks, and each has different purposes.
The longer version
Life is so diverse and unwieldy, it may surprise you to learn that we can break it down into four basic categories of molecules. Possibly even more implausible is the fact that two of these categories of large molecules themselves break down into a surprisingly small number of building blocks. The proteins that make up all of the living things on this planet and ensure their appropriate structure and smooth function consist of only 20 different kinds of building blocks. Nucleic acids, specifically DNA, are even more basic: only four different kinds of molecules provide the materials to build the countless different genetic codes that translate into all the different walking, swimming, crawling, oozing, and/or photosynthesizing organisms that populate the third rock from the Sun.


Big Molecules with Small Building Blocks

The functional groups, assembled into building blocks on backbones of carbon atoms, can be bonded together to yield large molecules that we classify into four basic categories. These molecules, in many different permutations, are the basis for the diversity that we see among living things. They can consist of thousands of atoms, but only a handful of different kinds of atoms form them. It’s like building apartment buildings using a small selection of different materials: bricks, mortar, iron, glass, and wood. Arranged in different ways, these few materials can yield a huge variety of structures.

We encountered functional groups and the SPHONC in Chapter 3. These components form the four categories of molecules of life. These Big Four biological molecules are carbohydrates, lipids, proteins, and nucleic acids. They can have many roles, from giving an organism structure to being involved in one of the millions of processes of living. Let’s meet each category individually and discover the basic roles of each in the structure and function of life.

You have met carbohydrates before, whether you know it or not. We refer to them casually as “sugars,” molecules made of carbon, hydrogen, and oxygen. A sugar molecule has a carbon backbone, usually five or six carbons in the ones we’ll discuss here, but it can be as few as three. Sugar molecules can link together in pairs or in chains or branching “trees,” either for structure or energy storage.

When you look on a nutrition label, you’ll see reference to “sugars.” That term includes carbohydrates that provide energy, which we get from breaking the chemical bonds in a sugar called glucose. The “sugars” on a nutrition label also include those that give structure to a plant, which we call fiber. Both are important nutrients for people.

Sugars serve many purposes. They give crunch to the cell walls of a plant or the exoskeleton of a beetle and chemical energy to the marathon runner. When attached to other molecules, like proteins or fats, they aid in communication between cells. But before we get any further into their uses, let’s talk structure.

The sugars we encounter most in basic biology have their five or six carbons linked together in a ring. There’s no need to dive deep into organic chemistry, but there are a couple of essential things to know to interpret the standard representations of these molecules.

Check out the sugars depicted in the figure. The top-left molecule, glucose, has six carbons, which have been numbered. The sugar to its right is the same glucose, with all but one “C” removed. The other five carbons are still there but are inferred using the conventions of organic chemistry: Anywhere there is a corner, there’s a carbon unless otherwise indicated. It might be a good exercise for you to add in a “C” over each corner so that you gain a good understanding of this convention. You should end up adding in five carbon symbols; the sixth is already given because that is conventionally included when it occurs outside of the ring.

On the left is a glucose with all of its carbons indicated. They’re also numbered, which is important to understand now for information that comes later. On the right is the same molecule, glucose, without the carbons indicated (except for the sixth one). Wherever there is a corner, there is a carbon, unless otherwise indicated (as with the oxygen). On the bottom left is ribose, the sugar found in RNA. The sugar on the bottom right is deoxyribose. Note that at carbon 2 (*), the ribose and deoxyribose differ by a single oxygen.

The lower left sugar in the figure is a ribose. In this depiction, the carbons, except the one outside of the ring, have not been drawn in, and they are not numbered. This is the standard way sugars are presented in texts. Can you tell how many carbons there are in this sugar? Count the corners and don’t forget the one that’s already indicated!

If you said “five,” you are right. Ribose is a pentose (pent = five) and happens to be the sugar present in ribonucleic acid, or RNA. Think to yourself what the sugar might be in deoxyribonucleic acid, or DNA. If you thought, deoxyribose, you’d be right.

The fourth sugar given in the figure is a deoxyribose. In organic chemistry, it’s not enough to know that corners indicate carbons. Each carbon also has a specific number, which becomes important in discussions of nucleic acids. Luckily, we get to keep our carbon counting pretty simple in basic biology. To count carbons, you start with the carbon to the right of the non-carbon corner of the molecule. The deoxyribose or ribose always looks to me like a little cupcake with a cherry on top. The “cherry” is an oxygen. To the right of that oxygen, we start counting carbons, so that corner to the right of the “cherry” is the first carbon. Now, keep counting. Here’s a little test: What is hanging down from carbon 2 of the deoxyribose?

If you said a hydrogen (H), you are right! Now, compare the deoxyribose to the ribose. Do you see the difference in what hangs off of the carbon 2 of each sugar? You’ll see that the carbon 2 of ribose has an –OH, rather than an H. The reason the deoxyribose is called that is because the O on the second carbon of the ribose has been removed, leaving a “deoxyed” ribose. This tiny distinction between the sugars used in DNA and RNA is significant enough in biology that we use it to distinguish the two nucleic acids.

In fact, these subtle differences in sugars mean big differences for many biological molecules. Below, you’ll find a couple of ways that apparently small changes in a sugar molecule can mean big changes in what it does. These little changes make the difference between a delicious sugar cookie and the crunchy exoskeleton of a dung beetle.

Sugar and Fuel

A marathon runner keeps fuel on hand in the form of “carbs,” or sugars. These fuels provide the marathoner’s straining body with the energy it needs to keep the muscles pumping. When we take in sugar like this, it often comes in the form of glucose molecules attached together in a polymer called starch. We are especially equipped to start breaking off individual glucose molecules the minute we start chewing on a starch.

Double X Extra: A monomer is a building block (mono = one) and a polymer is a chain of monomers. With a few dozen monomers or building blocks, we get millions of different polymers. That may sound nutty until you think of the infinity of values that can be built using only the numbers 0 through 9 as building blocks or the intricate programming that is done using only a binary code of zeros and ones in different combinations.

Our bodies then can rapidly take the single molecules, or monomers, into cells and crack open the chemical bonds to transform the energy for use. The bonds of a sugar are packed with chemical energy that we capture to build a different kind of energy-containing molecule that our muscles access easily. Most species rely on this process of capturing energy from sugars and transforming it for specific purposes.

Polysaccharides: Fuel and Form

Plants use the Sun’s energy to make their own glucose, and starch is actually a plant’s way of storing up that sugar. Potatoes, for example, are quite good at packing away tons of glucose molecules and are known to dieticians as a “starchy” vegetable. The glucose molecules in starch are packed fairly closely together. A string of sugar molecules bonded together through dehydration synthesis, as they are in starch, is a polymer called a polysaccharide (poly = many; saccharide = sugar). When the monomers of the polysaccharide are released, as when our bodies break them up, the reaction that releases them is called hydrolysis.

Double X Extra: The specific reaction that hooks one monomer to another in a covalent bond is called dehydration synthesis because in making the bond–synthesizing the larger molecule–a molecule of water is removed (dehydration). The reverse is hydrolysis (hydro = water; lysis = breaking), which breaks the covalent bond by the addition of a molecule of water.

Although plants make their own glucose and animals acquire it by eating the plants, animals can also package away the glucose they eat for later use. Animals, including humans, store glucose in a polysaccharide called glycogen, which is more branched than starch. In us, we build this energy reserve primarily in the liver and access it when our glucose levels drop.

Whether starch or glycogen, the glucose molecules that are stored are bonded together so that all of the molecules are oriented the same way. If you view the sixth carbon of the glucose to be a “carbon flag,” you’ll see in the figure that all of the glucose molecules in starch are oriented with their carbon flags on the upper left.

The orientation of monomers of glucose in polysaccharides can make a big difference in the use of the polymer. The glucoses in the molecule on the top are all oriented “up” and form starch. The glucoses in the molecule on the bottom alternate orientation to form cellulose, which is quite different in its function from starch.

Storing up sugars for fuel and using them as fuel isn’t the end of the uses of sugar. In fact, sugars serve as structural molecules in a huge variety of organisms, including fungi, bacteria, plants, and insects.

The primary structural role of a sugar is as a component of the cell wall, giving the organism support against gravity. In plants, the familiar old glucose molecule serves as one building block of the plant cell wall, but with a catch: The molecules are oriented in an alternating up-down fashion. The resulting structural sugar is called cellulose.

That simple difference in orientation means the difference between a polysaccharide as fuel for us and a polysaccharide as structure. Insects take it step further with the polysaccharide that makes up their exoskeleton, or outer shell. Once again, the building block is glucose, arranged as it is in cellulose, in an alternating conformation. But in insects, each glucose has a little extra added on, a chemical group called an N-acetyl group. This addition of a single functional group alters the use of cellulose and turns it into a structural molecule that gives bugs that special crunchy sound when you accidentally…ahem…step on them.

These variations on the simple theme of a basic carbon-ring-as-building-block occur again and again in biological systems. In addition to serving roles in structure and as fuel, sugars also play a role in function. The attachment of subtly different sugar molecules to a protein or a lipid is one way cells communicate chemically with one another in refined, regulated interactions. It’s as though the cells talk with each other using a specialized, sugar-based vocabulary. Typically, cells display these sugary messages to the outside world, making them available to other cells that can recognize the molecular language.

Lipids: The Fatty Trifecta

Starch makes for good, accessible fuel, something that we immediately attack chemically and break up for quick energy. But fats are energy that we are supposed to bank away for a good long time and break out in times of deprivation. Like sugars, fats serve several purposes, including as a dense source of energy and as a universal structural component of cell membranes everywhere.

Fats: the Good, the Bad, the Neutral

Turn again to a nutrition label, and you’ll see a few references to fats, also known as lipids. (Fats are slightly less confusing that sugars in that they have only two names.) The label may break down fats into categories, including trans fats, saturated fats, unsaturated fats, and cholesterol. You may have learned that trans fats are “bad” and that there is good cholesterol and bad cholesterol, but what does it all mean?

Let’s start with what we mean when we say saturated fat. The question is, saturated with what? There is a specific kind of dietary fat call the triglyceride. As its name implies, it has a structural motif in which something is repeated three times. That something is a chain of carbons and hydrogens, hanging off in triplicate from a head made of glycerol, as the figure shows.  Those three carbon-hydrogen chains, or fatty acids, are the “tri” in a triglyceride. Chains like this can be many carbons long.

Double X Extra: We call a fatty acid a fatty acid because it’s got a carboxylic acid attached to a fatty tail. A triglyceride consists of three of these fatty acids attached to a molecule called glycerol. Our dietary fat primarily consists of these triglycerides.

Triglycerides come in several forms. You may recall that carbon can form several different kinds of bonds, including single bonds, as with hydrogen, and double bonds, as with itself. A chain of carbon and hydrogens can have every single available carbon bond taken by a hydrogen in single covalent bond. This scenario of hydrogen saturation yields a saturated fat. The fat is saturated to its fullest with every covalent bond taken by hydrogens single bonded to the carbons.

Saturated fats have predictable characteristics. They lie flat easily and stick to each other, meaning that at room temperature, they form a dense solid. You will realize this if you find a little bit of fat on you to pinch. Does it feel pretty solid? That’s because animal fat is saturated fat. The fat on a steak is also solid at room temperature, and in fact, it takes a pretty high heat to loosen it up enough to become liquid. Animals are not the only organisms that produce saturated fat–avocados and coconuts also are known for their saturated fat content.

The top graphic above depicts a triglyceride with the glycerol, acid, and three hydrocarbon tails. The tails of this saturated fat, with every possible hydrogen space occupied, lie comparatively flat on one another, and this kind of fat is solid at room temperature. The fat on the bottom, however, is unsaturated, with bends or kinks wherever two carbons have double bonded, booting a couple of hydrogens and making this fat unsaturated, or lacking some hydrogens. Because of the space between the bumps, this fat is probably not solid at room temperature, but liquid.

You can probably now guess what an unsaturated fat is–one that has one or more hydrogens missing. Instead of single bonding with hydrogens at every available space, two or more carbons in an unsaturated fat chain will form a double bond with carbon, leaving no space for a hydrogen. Because some carbons in the chain share two pairs of electrons, they physically draw closer to one another than they do in a single bond. This tighter bonding result in a “kink” in the fatty acid chain.

In a fat with these kinks, the three fatty acids don’t lie as densely packed with each other as they do in a saturated fat. The kinks leave spaces between them. Thus, unsaturated fats are less dense than saturated fats and often will be liquid at room temperature. A good example of a liquid unsaturated fat at room temperature is canola oil.

A few decades ago, food scientists discovered that unsaturated fats could be resaturated or hydrogenated to behave more like saturated fats and have a longer shelf life. The process of hydrogenation–adding in hydrogens–yields trans fat. This kind of processed fat is now frowned upon and is being removed from many foods because of its associations with adverse health effects. If you check a food label and it lists among the ingredients “partially hydrogenated” oils, that can mean that the food contains trans fat.

Double X Extra: A triglyceride can have up to three different fatty acids attached to it. Canola oil, for example, consists primarily of oleic acid, linoleic acid, and linolenic acid, all of which are unsaturated fatty acids with 18 carbons in their chains.

Why do we take in fat anyway? Fat is a necessary nutrient for everything from our nervous systems to our circulatory health. It also, under appropriate conditions, is an excellent way to store up densely packaged energy for the times when stores are running low. We really can’t live very well without it.

Phospholipids: An Abundant Fat

You may have heard that oil and water don’t mix, and indeed, it is something you can observe for yourself. Drop a pat of butter–pure saturated fat–into a bowl of water and watch it just sit there. Even if you try mixing it with a spoon, it will just sit there. Now, drop a spoon of salt into the water and stir it a bit. The salt seems to vanish. You’ve just illustrated the difference between a water-fearing (hydrophobic) and a water-loving (hydrophilic) substance.

Generally speaking, compounds that have an unequal sharing of electrons (like ions or anything with a covalent bond between oxygen and hydrogen or nitrogen and hydrogen) will be hydrophilic. The reason is that a charge or an unequal electron sharing gives the molecule polarity that allows it to interact with water through hydrogen bonds. A fat, however, consists largely of hydrogen and carbon in those long chains. Carbon and hydrogen have roughly equivalent electronegativities, and their electron-sharing relationship is relatively nonpolar. Fat, lacking in polarity, doesn’t interact with water. As the butter demonstrated, it just sits there.

There is one exception to that little maxim about fat and water, and that exception is the phospholipid. This lipid has a special structure that makes it just right for the job it does: forming the membranes of cells. A phospholipid consists of a polar phosphate head–P and O don’t share equally–and a couple of nonpolar hydrocarbon tails, as the figure shows. If you look at the figure, you’ll see that one of the two tails has a little kick in it, thanks to a double bond between the two carbons there.

Phospholipids form a double layer and are the major structural components of cell membranes. Their bend, or kick, in one of the hydrocarbon tails helps ensure fluidity of the cell membrane. The molecules are bipolar, with hydrophilic heads for interacting with the internal and external watery environments of the cell and hydrophobic tails that help cell membranes behave as general security guards.

The kick and the bipolar (hydrophobic and hydrophilic) nature of the phospholipid make it the perfect molecule for building a cell membrane. A cell needs a watery outside to survive. It also needs a watery inside to survive. Thus, it must face the inside and outside worlds with something that interacts well with water. But it also must protect itself against unwanted intruders, providing a barrier that keeps unwanted things out and keeps necessary molecules in.

Phospholipids achieve it all. They assemble into a double layer around a cell but orient to allow interaction with the watery external and internal environments. On the layer facing the inside of the cell, the phospholipids orient their polar, hydrophilic heads to the watery inner environment and their tails away from it. On the layer to the outside of the cell, they do the same.
As the figure shows, the result is a double layer of phospholipids with each layer facing a polar, hydrophilic head to the watery environments. The tails of each layer face one another. They form a hydrophobic, fatty moat around a cell that serves as a general gatekeeper, much in the way that your skin does for you. Charged particles cannot simply slip across this fatty moat because they can’t interact with it. And to keep the fat fluid, one tail of each phospholipid has that little kick, giving the cell membrane a fluid, liquidy flow and keeping it from being solid and unforgiving at temperatures in which cells thrive.

Steroids: Here to Pump You Up?

Our final molecule in the lipid fatty trifecta is cholesterol. As you may have heard, there are a few different kinds of cholesterol, some of which we consider to be “good” and some of which is “bad.” The good cholesterol, high-density lipoprotein, or HDL, in part helps us out because it removes the bad cholesterol, low-density lipoprotein or LDL, from our blood. The presence of LDL is associated with inflammation of the lining of the blood vessels, which can lead to a variety of health problems.

But cholesterol has some other reasons for existing. One of its roles is in the maintenance of cell membrane fluidity. Cholesterol is inserted throughout the lipid bilayer and serves as a block to the fatty tails that might otherwise stick together and become a bit too solid.

Cholesterol’s other starring role as a lipid is as the starting molecule for a class of hormones we called steroids or steroid hormones. With a few snips here and additions there, cholesterol can be changed into the steroid hormones progesterone, testosterone, or estrogen. These molecules look quite similar, but they play very different roles in organisms. Testosterone, for example, generally masculinizes vertebrates (animals with backbones), while progesterone and estrogen play a role in regulating the ovulatory cycle.

Double X Extra: A hormone is a blood-borne signaling molecule. It can be lipid based, like testosterone, or short protein, like insulin.


As you progress through learning biology, one thing will become more and more clear: Most cells function primarily as protein factories. It may surprise you to learn that proteins, which we often talk about in terms of food intake, are the fundamental molecule of many of life’s processes. Enzymes, for example, form a single broad category of proteins, but there are millions of them, each one governing a small step in the molecular pathways that are required for living.

Levels of Structure

Amino acids are the building blocks of proteins. A few amino acids strung together is called a peptide, while many many peptides linked together form a polypeptide. When many amino acids strung together interact with each other to form a properly folded molecule, we call that molecule a protein.

For a string of amino acids to ultimately fold up into an active protein, they must first be assembled in the correct order. The code for their assembly lies in the DNA, but once that code has been read and the amino acid chain built, we call that simple, unfolded chain the primary structure of the protein.

This chain can consist of hundreds of amino acids that interact all along the sequence. Some amino acids are hydrophobic and some are hydrophilic. In this context, like interacts best with like, so the hydrophobic amino acids will interact with one another, and the hydrophilic amino acids will interact together. As these contacts occur along the string of molecules, different conformations will arise in different parts of the chain. We call these different conformations along the amino acid chain the protein’s secondary structure.

Once those interactions have occurred, the protein can fold into its final, or tertiary structure and be ready to serve as an active participant in cellular processes. To achieve the tertiary structure, the amino acid chain’s secondary interactions must usually be ongoing, and the pH, temperature, and salt balance must be just right to facilitate the folding. This tertiary folding takes place through interactions of the secondary structures along the different parts of the amino acid chain.

The final product is a properly folded protein. If we could see it with the naked eye, it might look a lot like a wadded up string of pearls, but that “wadded up” look is misleading. Protein folding is a carefully regulated process that is determined at its core by the amino acids in the chain: their hydrophobicity and hydrophilicity and how they interact together.

In many instances, however, a complete protein consists of more than one amino acid chain, and the complete protein has two or more interacting strings of amino acids. A good example is hemoglobin in red blood cells. Its job is to grab oxygen and deliver it to the body’s tissues. A complete hemoglobin protein consists of four separate amino acid chains all properly folded into their tertiary structures and interacting as a single unit. In cases like this involving two or more interacting amino acid chains, we say that the final protein has a quaternary structure. Some proteins can consist of as many as a dozen interacting chains, behaving as a single protein unit.

A Plethora of Purposes

What does a protein do? Let us count the ways. Really, that’s almost impossible because proteins do just about everything. Some of them tag things. Some of them destroy things. Some of them protect. Some mark cells as “self.” Some serve as structural materials, while others are highways or motors. They aid in communication, they operate as signaling molecules, they transfer molecules and cut them up, they interact with each other in complex, interrelated pathways to build things up and break things down. They regulate genes and package DNA, and they regulate and package each other.

As described above, proteins are the final folded arrangement of a string of amino acids. One way we obtain these building blocks for the millions of proteins our bodies make is through our diet. You may hear about foods that are high in protein or people eating high-protein diets to build muscle. When we take in those proteins, we can break them apart and use the amino acids that make them up to build proteins of our own.

Nucleic Acids

How does a cell know which proteins to make? It has a code for building them, one that is especially guarded in a cellular vault in our cells called the nucleus. This code is deoxyribonucleic acid, or DNA. The cell makes a copy of this code and send it out to specialized structures that read it and build proteins based on what they read. As with any code, a typo–a mutation–can result in a message that doesn’t make as much sense. When the code gets changed, sometimes, the protein that the cell builds using that code will be changed, too.

Biohazard!The names associated with nucleic acids can be confusing because they all start with nucle-. It may seem obvious or easy now, but a brain freeze on a test could mix you up. You need to fix in your mind that the shorter term (10 letters, four syllables), nucleotide, refers to the smaller molecule, the three-part building block. The longer term (12 characters, including the space, and five syllables), nucleic acid, which is inherent in the names DNA and RNA, designates the big, long molecule.

DNA vs. RNA: A Matter of Structure

DNA and its nucleic acid cousin, ribonucleic acid, or RNA, are both made of the same kinds of building blocks. These building blocks are called nucleotides. Each nucleotide consists of three parts: a sugar (ribose for RNA and deoxyribose for DNA), a phosphate, and a nitrogenous base. In DNA, every nucleotide has identical sugars and phosphates, and in RNA, the sugar and phosphate are also the same for every nucleotide.

So what’s different? The nitrogenous bases. DNA has a set of four to use as its coding alphabet. These are the purines, adenine and guanine, and the pyrimidines, thymine and cytosine. The nucleotides are abbreviated by their initial letters as A, G, T, and C. From variations in the arrangement and number of these four molecules, all of the diversity of life arises. Just four different types of the nucleotide building blocks, and we have you, bacteria, wombats, and blue whales.

RNA is also basic at its core, consisting of only four different nucleotides. In fact, it uses three of the same nitrogenous bases as DNA–A, G, and C–but it substitutes a base called uracil (U) where DNA uses thymine. Uracil is a pyrimidine.

DNA vs. RNA: Function Wars

An interesting thing about the nitrogenous bases of the nucleotides is that they pair with each other, using hydrogen bonds, in a predictable way. An adenine will almost always bond with a thymine in DNA or a uracil in RNA, and cytosine and guanine will almost always bond with each other. This pairing capacity allows the cell to use a sequence of DNA and build either a new DNA sequence, using the old one as a template, or build an RNA sequence to make a copy of the DNA.

These two different uses of A-T/U and C-G base pairing serve two different purposes. DNA is copied into DNA usually when a cell is preparing to divide and needs two complete sets of DNA for the new cells. DNA is copied into RNA when the cell needs to send the code out of the vault so proteins can be built. The DNA stays safely where it belongs.

RNA is really a nucleic acid jack-of-all-trades. It not only serves as the copy of the DNA but also is the main component of the two types of cellular workers that read that copy and build proteins from it. At one point in this process, the three types of RNA come together in protein assembly to make sure the job is done right.

 By Emily Willingham, DXS managing editor 
This material originally appeared in similar form in Emily Willingham’s Complete Idiot’s Guide to College Biology

From spiders to breast cancer: Leslie Brunetta talks candidly about her cancer diagnosis, treatment, and follow-up

According to Leslie Brunetta, she now has much more hair than she had last July.
We became aware of Leslie Brunetta because of her book, Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating, co-authored with Catherine L. Craig. Thanks to a piece Leslie wrote for the Concord Monitor (and excerpted here), we also learned that she is a breast cancer survivor. Leslie agreed to an interview about her experience, and in her emailed responses, she candidly talks about her diagnosis, treatment, and follow-up for her cancers, plural: She was diagnosed simultaneously with two types of breast cancer. 
DXS: In your Concord Monitor piece, you describe the link between an understanding of the way evolution happens and some of the advances in modern medicine. What led you to grasp the link between the two?

LB: I think, because I’m not a scientist (I’m an English major), a lot of things that scientists think are obvious strike me as revelations. I somehow had never realized that the search for what would turn out to be DNA began with trying to explain how, in line with the theory of evolution by natural selection, variation arises and traits are passed from generation to generation. As I was figuring out what each chapter in Spider Silk would be about, I tried to think about the questions non-biologists like me would still have about evolution when they got to that point in the book. By the time we got past dragline silk, I realized that we had so far fleshed out the ways that silk proteins could and have evolved at the genetic level. But that explanation probably wouldn’t answer readers’ questions about how, for example, abdominal spinnerets—which are unique to spiders—might have evolved: the evolution of silk is easier to untangle than the evolution of body parts, which is why we focused on it in the first place.

I decided I wanted to write a chapter on “evo-devo,” evolutionary developmental biology, partly because there was a cool genetic study on the development of spinnerets that showed they’ve evolved from limbs. Fortunately, my co-author, Cay Craig, and editor at Yale, Jean Thomson Black, okayed the idea, because that chapter wasn’t in the original proposal. Writing that chapter, I learned why it took so long—nearly a century—to get from Darwin and Mendel to Watson and Crick and then so long again to get to where we are today. If we non-scientists understand something scientific, it’s often how it works, not how a whole string of people over the course of decades building on each other’s work discovered how it works. I knew evolution was the accumulation of gene changes, but, until I wrote that chapter, it hadn’t occurred to me that people began to look for genes because they wanted to understand evolution.

So that was all in the spider part of my life. Then, a few months into the cancer part of my life, I was offered a test called Oncotype DX, which would look at genetic markers in my tumor cells to develop a risk profile that could help me decide whether I should have chemotherapy plus tamoxifen or just tamoxifen. The results turned out to be moot in my case because I had a number of positive lymph nodes, although it was reassuring to find out that the cancer was considered low risk for recurrence. But still—the idea that a genetic test could let some women avoid chemo without taking on extra risk, that’s huge. No one would want to go through chemo if it wasn’t necessary. So by then I was thinking, “Thank you, Darwin!”

And then, coincidentally, the presidential primary season was heating up, and there were a number of serious candidates (well, serious in the sense that they had enough backing to get into the debates) who proudly declared that they had no time for the theory of evolution. And year after year these stupid anti-evolution bills are introduced in various state legislatures. While I was lying on the couch hanging out in the days after chemo sessions, I started thinking, “So, given that you don’t give any credence to Darwin and his ideas, would you refuse on principle to take the Oncotype test or gene-based therapies like Gleevec or Herceptin if you had cancer or if someone in your family had cancer? Somehow I don’t think so.” That argument is not going to convince hard-core denialists (nothing will), but maybe the cognitive dissonance in connection with something as concrete as cancer will make some people who waver want to find out more.

DXS: You mention having been diagnosed with two different forms of cancer, one in each breast. Can you say what each kind was and, if possible, how they differed?

LB: Yes, I unfortunately turned out to be an “interesting” case. This is one arena where, if you possibly can, you want to avoid being interesting. At first it seemed that I had a tiny lesion that was an invasive ductal carcinoma (IDC) and that I would “just” need a lumpectomy and radiation. Luckily for me, the doctor reading my mammogram is known as an eagle eye, and she saw a few things that—given the positive finding from the biopsy—concerned her. She recommended an MRI. In fact, even though I switched to another hospital for my surgery, she sent emails there saying I should have an MRI. That turned up “concerning” spots in both breasts, which led to more biopsies, which revealed multiple tiny cancerous lesions. The only reasonable option was then a double mastectomy.

The lesions in the right breast were IDCs. About 70% of breast cancers are diagnosed as IDCs. Those cancers start with the cells lining the milk ducts. The ones in the left breast were invasive lobular carcinomas (ILCs), which start in the lobules at the end of the milk ducts. Only about 10% of breast cancers are ILCs.

Oncologists hate lobular cancer. Unlike ductal cancers, which form as clumps of cells, lobular cancers form as single-file ribbons of cells. The tissue around ductal cancer cells reacts to those cells, which is why someone may feel a lump—she’s (or he’s) not feeling the cancer itself but the inflammation of the tissue around it. And because the cells clump, they show up more readily on mammograms. Not so lobular cancers. They mostly don’t give rise to lumps and they’re hard to spot on mammograms. They snake their way through tissue for quite a while without bothering anything.

In my case, this explains why last spring felt like an unremitting downhill slide. Every time someone looked deeper, they found something worse. It turned out that on my left side, the lobular side, I had multiple positive lymph nodes, which was why I needed not just chemo but also radiation (which usually isn’t given after a mastectomy). That was the side that didn’t even show up much on the mammogram. On the right side, the ductal side, which provoked the initial suspicions, my nodes were clear. I want to write about this soon, because I want to find out more about it. I’ve only recently gotten to the place emotionally where I think I can deal with reading the research papers as opposed to more general information. By the way, the resource that most helped us better understand what my doctors were talking about was Dr. Susan Love’s Breast Book.  It was invaluable as we made our way through this process, although it turned out that I had very few decisions to make because there was usually only one good option.   

DXS: As part of your treatment, you had a double mastectomy. One of our goals with this interview is to tell women what some of these experiences with treatment are like. If you’re comfortable doing so, could you tell us a little bit about what a double mastectomy entails and what you do after one in practical terms?

LB: A mastectomy is a strange operation. In a way, it’s more of an emotional and psychological experience than a physical experience. My surgeon, who was fantastic, is a man, and when we discussed the need for the mastectomies he said that I would be surprised at how little pain would be involved and how quick the healing would be. Even though I trusted him a lot by then, my reaction was pretty much, “Like you would know, right?” But he did know. When you think about it, it’s fairly non-invasive surgery. Unless the cancer has spread to the surrounding area, which doesn’t happen very often now due to early detection, no muscle or bone is removed. (Until relatively recently, surgeons removed the major muscle in the chest wall, and sometimes even bone, because they believed it would cut the risk of recurrence. That meant that many women lost function in their arm and also experienced back problems.) None of your organs are touched. They don’t go into your abdominal cavity. Also, until recently, they removed a whole clump of underarm lymph nodes when they did lumpectomies or mastectomies. Now they usually remove just a “sentinel node,” because they know that it will give them a fairly reliable indicator of whether the cancer has spread to the other nodes. That also makes the surgery less traumatic than it used to be.

I opted not to have reconstruction. Reconstruction is a good choice for many women, but I didn’t see many benefits for me and I didn’t like the idea of a more complicated surgery. My surgery was only about two hours. I don’t remember any pain at all afterwards, and my husband says I never complained of any. I was in the hospital for just one night. By the next day, I was on ibuprofen only. The bandages came off two days after the surgery.

That’s shocking, to see your breasts gone and replaced by thin red lines, no matter how well you’ve prepared yourself. It made the cancer seem much more real in some way than it had seemed before. In comparison, the physical recovery from the surgery was fairly minor because I had no infections or complications. There were drains in place for about 10 days to collect serum, which would otherwise collect under the skin, and my husband dealt with emptying them twice a day and measuring the amount. I had to sleep on my back, propped up, because of where the drains were placed, high up on my sides, and I never really got used to that. It was a real relief to have the drains removed.

My surgeon told me to start doing stretching exercises with my arms right away, and that’s really important. I got my full range of motion back within a couple of months. But even though I had my surgery last March, I’ve noticed lately that if I don’t stretch fully, like in yoga, things tighten up. That may be because of the radiation, though, because it’s only on my left side. Things are never quite the same as they were before the surgery, though. Because I did have to have the axillary nodes out on my left side, my lymph system is disrupted. I haven’t had any real problems with lymphedema yet, and I may never, but in the early months I noticed that my hands would swell if I’d been walking around a lot, and I’d have to elevate them to get them to drain back. That rarely happens now. But I’ve been told I need to wear a compression sleeve if I fly because the change in air pressure can cause lymph to collect. Also, I’m supposed to protect my hands and arms from cuts as much as possible. It seems to me that small nicks on my fingers take longer to heal than they used to. So even though most of the time it seems like it’s all over, I guess in those purely mechanical ways it’s never over. It’s not just that you no longer have breasts, it’s also that nerves and lymph channels and bits of tissue are also missing or moved around.

The bigger question is how one deals with now lacking breasts. I’ve decided not to wear prostheses. I can get away with it because I was small breasted, I dress in relatively loose clothes anyway, and I’ve gained confidence over time that no one notices or cares and I care less now if they do notice. But getting that self-confidence took quite a while. Obviously, it has an effect on my sex life, but we have a strong bond and it’s just become a piece of that bond. The biggest thing is that it’s always a bit of a shock when I catch sight of myself naked in a mirror because it’s a reminder that I’ve had cancer and there’s no getting around the fact that that sucks.    

DXS: My mother-in-law completed radiation and chemo for breast cancer last year, and if I remember correctly, she had to go frequently for a period of weeks for radiation. Was that you experience? Can you describe for our readers what the time investment was like and what the process was like?

LB: I went for radiation 5 days a week for about 7 weeks. Three days a week, I’d usually be in and out of the hospital within 45 minutes. One day a week, I met with the radiology oncologist and a nurse to debrief, which was also a form of emotional therapy for me. And one day a week, they laid on a chair massage, and the nurse/massage therapist who gave the massage was great to talk to, so that was more therapy. Radiation was easy compared to chemo. Some people experience skin burning and fatigue, but I was lucky that I didn’t experience either. Because I’m a freelancer, the time investment wasn’t a burden for me. I’m also lucky living where I live, because I could walk to the hospital. It was a pleasant 3-mile round-trip walk, and I think the walking helped me a lot physically and mentally.
DXS: And now to the chemo. My interest in interviewing you about your experience began with a reference you made on Twitter to “chemo brain,” and of course, after reading your evolution-medical advances piece. Can you tell us a little about what the process of receiving chemotherapy is like? How long does it take? How frequently (I know this varies, but your experience)?
LB: Because of my age (I was considered young, which was always nice to hear) and state of general good health, my oncologist put me on a dose-dense AC-T schedule. This meant going for treatment every two weeks over the course of 16 weeks—8 treatment sessions. At the first 4 sessions, I was given Adriamycin and Cytoxan (AC), and the last 4 sessions I was given Taxol (T). The idea behind giving multiple drugs and giving them frequently is that they all attack cancer cells in different ways and—it goes back to evolution—by attacking them frequently and hard on different fronts, you’re trying to avoid selecting for a population that’s resistant to one or more of the drugs. They can give the drugs every two weeks to a lot of patients now because they’ve got drugs to boost the production of white blood cells, which the cancer drugs suppress. After most chemo sessions, I went back the next day for a shot of one of these drugs, Neulasta.

The chemo clinic was, bizarrely, a very relaxing place. The nurses who work there were fantastic, and the nurse assigned to me, Kathy, was always interesting to talk with. She had a great sense of humor, and she was also interested in the science behind everything we were doing, so if I ever had questions she didn’t have ready answers for, she’d find out for me. A lot of patients were there at the same time, but we each had a private space. You’d sit in a big reclining chair. They had TVs and DVDs, but I usually used it as an opportunity to read. My husband sat through the first session with me, and a close friend who had chemo for breast cancer 15 years ago sat through a few other sessions, but once I got used to it, I was comfortable being there alone. Because of the nurses, it never felt lonely.

I’d arrive and settle in. Kathy would take blood for testing red and white blood counts and, I think, liver function and some other things, and she’d insert a needle and start a saline drip while we waited for the results. I’ve always had large veins, so I opted to have the drugs administered through my arm rather than having a port implanted in my chest. Over the course of three to four hours, she’d change the IV bags. Some of the bags were drugs to protect against nausea, so I’d start to feel kind of fuzzy—I don’t think I retained a whole lot of what I read there! The Adriamycin was bright orange; they call it the Red Devil, because it can chew up your veins—sometimes it felt like it was burning but Kathy could stop that by slowing the drip. Otherwise, it was fairly uneventful. I’d have snacks and usually ate lunch while still hooked up.

I was lucky I never had any reactions to any of the drugs, so actually getting the chemo was a surprisingly pleasant experience just because of the atmosphere. On the one hand, you’re aware of all these people around you struggling with cancer and you know things aren’t going well for some of them, so it’s heartbreaking, and also makes you consider, sometimes fearfully, your own future no matter how well you’re trying to brace yourself up. But at the same time, the people working there are so positive, but not in a Pollyannaish-false way, that they helped me as I tried to stay positive. The social worker stopped in with each patient every session, and she was fantastic—I could talk out any problems or fears I had with her, and that helped a huge amount.

DXS: Would you be able to run us through a timeline of the physical effects of chemotherapy after an infusion? How long does it take before it hits hardest? My mother-in-law told me that her biggest craving, when she could eat, was for carb-heavy foods like mashed potatoes and for soups, like vegetable soup. What was your experience with that?

LB: My biggest fear when I first learned I would need chemo was nausea. My oncologist told us that they had nausea so well controlled that over the past few years, she had only had one or two patients who had experienced it. As with the surgeon’s prediction about mastectomy pain, this turned out to be true: I never had even a single moment of nausea.

But there were all sorts of other effects. For the first few days after a session, the most salient effects were actually from the mix of drugs I took to stave off nausea. I generally felt pretty fuzzy, but not necessarily sleepy—part of the mix was steroids, so you’re a little hyped. There’s no way I’d feel safe driving on those days, for example. I’d sleep well the first three nights because I took Ativan, which has an anti-nausea effect. But except for those days, my sleep was really disrupted. Partly that’s because, I’m guessing, the chemo hits certain cells in your brain and partly it’s because you get thrown into chemical menopause, so there were a lot of night hot flashes. Even though I’d already started into menopause, this chemo menopause was a lot more intense and included all the symptoms regularly associated with menopause.

By the end of the first session, I was feeling pretty joyful because it was much less bad than I had thought it would be. By the second week in the two-week cycle, I felt relatively normal. But even though it never got awful, the effects started to accumulate. My hair started to fall out the morning I was going to an award ceremony for Spider Silk. It was ok at the ceremony, but we shaved it off that night. I decided not to wear a wig. First, it was the summer, and it would have been hot. Second, I usually have close to a buzz cut, and I can’t imagine anyone would make a wig that would look anything like my hair. My kids’ attitude was that everyone would know something was wrong anyway, so I should just be bald, and that helped a lot. But it’s hard to see in people’s eyes multiple times a day their realization that you’re in a pretty bad place. Also, it’s not just your head hair that goes. So do your eyebrows, your eyelashes, your pubic hair, and most of the tiny hairs all over your skin. And as your skin cells are affected by the chemo (the chemo hits all fast-reproducing cells), your skin itself gets more sensitive and then is not protected by those tiny hairs. I remember a lot of itching. And strange things like my head sticking to my yoga mat and my reading glasses sticking to the side of my head instead of sliding over my ears.

I never lost my appetite, but I did have food cravings during the AC cycles. I wanted sushi and seaweed salad, of all things. And steak. My sense of taste went dull, so I also wanted things that tasted strong and had crunch. I stopped drinking coffee and alcohol, partly because of the sleep issues but partly because it didn’t taste very good anyway. I drank loads of water on the advice of the oncologist, the nurses, and my acupuncturist, and I think that helped a lot.

During the second cycle, I developed a fever. That was scary. I was warned that if I ever developed a fever, I should call the oncologist immediately, no matter the time of day or day of week. The problem is that your immune response is knocked down by the chemo, so what would normally be a small bacterial infection has the potential to rage out of control. I was lucky. We figured out that the source of infection was a hemorrhoid—the Adriamycin was beginning to chew into my digestive tract, a well-known side effect. (Having to pay constant attention to yet another usually private part of the body just seemed totally unfair by this point.) Oral antibiotics took care of it, which was great because I avoided having to go into the hospital and all the risks entailed with getting heavy-duty IV antibiotic treatment. And we were also able to keep on schedule with the chemo regimen, which is what you hope for.

After that, I became even more careful about avoiding infection, so I avoided public places even more than I had been. I’m very close to a couple of toddlers, and I couldn’t see them for weeks because they were in one of those toddler constant-viral stages, and I really missed them.

The Taxol seems to be much less harsh than the AC regimen, so a lot of these side effects started to ease off a bit by the second 8 weeks, which was certainly a relief.

I was lucky that I didn’t really have mouth sores or some of the other side effects. Some of this is, I think, just because besides the cancer I don’t have any other health issues. Some of it is because my husband took over everything and I don’t have a regular job, so I had the luxury of concentrating on doing what my body needed. I tried to walk every day, and I slept when I needed to, ate when and what I needed to, and went to yoga class when my immune system was ok. I also went to acupuncture every week. I know the science is iffy on that, but I think it helped me with the side effects, even if it was the placebo effect at work (I’m a big fan of the placebo effect). We also both had extraordinary emotional support from many friends and knew we could call lots of people if we needed anything. That’s huge when you’re in this kind of situation.

Currently, I’m still dealing with some minor joint pains, mostly in my wrists and feet. I wasn’t expecting this problem, but my oncologist says it’s not uncommon: they think it’s because your immune system has to re-find its proper level of function, and it can go into overdrive and set up inflammation in the joints. That’s gradually easing off, though.

Most people don’t have it as easy as I did in terms of the medical, financial, and emotional resources I had to draw on. I’m very mindful of that and very grateful.

DXS: You say that you had “few terrible side effects” and a “very cushy home situation.” I’m sure any woman would like to at least be able to experience the latter while dealing with a full-body chemical attack. What were some factors that made it “cushy” that women might be able to talk to their families or caregivers about replicating for them?

LB: As I’ve said, some of it is just circumstance. For example, my kids were old enough to be pretty self-sufficient and old enough to understand what was going on, which meant both that they needed very little from me in terms of care and also that they were less scared than they might have been if they were younger. My husband happens to be both very competent (more competent than I am) around the house and very giving. I live in Cambridge, MA, where I could actually make choices about where I wanted to be treated at each phase and know I’d get excellent, humane care and where none of the facilities I went to was more than about 20 minutes away.

Some things that women might have some control over and that their families might help nudge them toward:

  • Find doctors you trust. Ask a lot of questions and make sure you understand the answers. But don’t get hung up on survival or recurrence statistics. There’s no way to know for sure what your individual outcome will be. Go for the treatment that you and your doctors believe will give you the best chance, and then assume as much as possible that your outcome will be good.
  • Make sure you talk regularly with a social worker or other therapist who specializes in dealing with breast cancer patients. If you have fears or worries that you don’t want to talk to your partner or family about, here’s where you’ll get lots of help.
  • Find compatible friends who have also had cancer to talk to. I had friends who showed me their mastectomy scars, who showed me their reconstructions, who told me about their experiences with chemo and radiation, who told me about what life after treatment was like (is still like decades later…). And none of them told me, “You should…” They all just told me what was hard for them and what worked for them and let me figure out what worked for me. Brilliant.
  • Try to get some exercise even if you don’t feel like it. It was often when I felt least like moving around that a short walk made me feel remarkably better. But I would forget that, so my husband would remind me. Ask someone to walk with you if you’re feeling weak. Getting your circulation going seems to help the body process the chemo drugs and the waste products they create. For the same reason, drink lots of water.
  • Watch funny movies together. Laughter makes a huge difference.
  • Pamper yourself as much as possible. Let people take care of you and help as much as they’re willing. But don’t be afraid to say no to anything that you don’t want or that’s too much.

Family members and caregivers should also take care of themselves by making some time for themselves and talking to social workers or therapists if they feel the need. It’s a big, awful string of events for everyone involved, not just the patient.

DXS: In the midst of all of this, you seem to have written a fascinating book about spiders and their webs. Were you able to work while undergoing your treatments? Were there times that were better than others for attending to work? Could work be a sort of occupational therapy, when it was possible for you to do it, to keep you engaged?

LB: The book had been published about 6 months before my diagnosis. The whole cancer thing really interfered not with the writing, but with my efforts to publicize it. I had started to build toward a series of readings and had to abandon that effort. I had also started a proposal for a new book and had to put that aside. I had one radio interview in the middle of chemo, which was kind of daunting but I knew I couldn’t pass up the opportunity, and when I listen to it now, I can hear my voice sounds kind of shaky. It went well, but I was exhausted afterwards. Also invigorated, though—it made me feel like I hadn’t disappeared into the cancer. I had two streams of writing going on, both of which were therapeutic. I sent email updates about the cancer treatment to a group of friends—that was definitely psychological therapy. I also tried to keep the Spider Silk blog up to date by summarizing related research papers and other spider silk news—that was intellectual therapy. I just worked on them when I felt I wanted to. The second week of every cycle my head was usually reasonably clear.

I don’t really know whether I have chemo brain. I notice a lot of names-and-other-proper-nouns drop. But whether that’s from the chemo per se, or from the hormone changes associated with the chemically induced menopause, or just from emotional overload and intellectual distraction, I don’t know. I find that I’m thinking more clearly week by week.

DXS: What is the plan for your continued follow-up? How long will it last, what is the frequency of visits, sorts of tests, etc.?

LB: I’m on tamoxifen and I’ll be on that for probably two years and then either stay on that or go onto an aromatase inhibitor [Ed. note: these drugs block production of estrogen and are used for estrogen-sensitive cancers.] for another three years. I’ll see one of the cancer doctors every three months for at least a year, I think. They’ll ask me questions and do a physical exam and take blood samples to test for tumor markers. At some point the visits go to every six months.

For self-care, I’m exercising more, trying to lose some weight, and eating even better than I was before.

DXS: Last…if you’re comfortable detailing it…what led to your diagnosis in the first place?

LB: My breast cancer was uncovered by my annual mammogram. I’ve worried about cancer, as I suppose most people do. But I never really worried about breast cancer. My mother has 10 sisters and neither she nor any of them ever had breast cancer. I have about 20 older female cousins—I was 50 when I was diagnosed last year–and as far as I know none of them have had breast cancer. I took birth control pills for less than a year decades ago. Never smoked. Light drinker. Not overweight. Light exerciser. I breastfed both kids, although not for a full year. Never took replacement hormones. Never worked in a dangerous environment. Never had suspicious mammograms before. So on paper, I was at very low risk as far as I can figure out. After I finished intensive treatment, I was tested for BRCA1 and BRCA2 (because mutations there are associated with cancer in both breasts) and no mutations were found. Unless or until some new genetic markers are found and one of them applies to me, I think we’ll never know why I got breast cancer, other than the fact that I’ve lived long enough to get cancer. There was no lump. Even between the suspicious mammogram and ultrasound and the biopsy, none of the doctors examining me could feel a lump or anything irregular. It was a year ago this week that I got the news that the first biopsy was positive. In some ways, because I feel really good now, it’s hard to believe that this year ever happened. But in other ways, the shock of it is still with me and with the whole family. Things are good for now, though, and although I feel very unlucky that this happened in the first place, I feel extremely lucky with the medical care I received and the support I got from family and friends and especially my husband.
Leslie Brunetta’s articles and essays have appeared in the New York Times, Technology Review, and the Sewanee Review as well as on NPR and elsewhere. She is co-author, with Catherine L. Craig, of Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating (Yale University Press).

How helpful are dense-breast right-to-know laws?

A doctor reviews a digital mammogram, pointing to a possible cancer.
Credit: National Cancer Institute.
By Laura Newman, DXS contributor
In a victory for the dense-breast patient movement, Governor Jerry Brown (D-CA) signed legislation last week requiring that doctors who discover that women have dense breasts on mammography must inform women that:

§  dense breasts are a risk factor for breast cancer;
§  mammography sees cancer less well in dense breasts than in normal breasts; and
§  women may benefit from additional breast cancer screening.

The California law goes into effect on April 1, 2013. It follows four states (Connecticut, Texas, Virginia, and New York) with similar statutes. All have enjoyed solid bipartisan support. Rarely do naysayers or skeptics speak up.
Young women who are leading the charge often bring lawmakers the story of a young constituent, diagnosed with a very aggressive, lethal cancer that was not shown on film-screen mammography. The Are You Dense? patient advocacy group engages patients on Facebook, where women share their experiences with breast cancer, organize events, and lobby for legislation. Individual radiologists work with the advocacy groups, but many radiology groups and breast surgeons do not endorse these laws.

A Closer Look at Breast Cancer Data

Living in an age when information is viewed as an entitlement, knowledge, and power, many physicians find it hard to argue against a patient’s right to know. Can sharing information be a mistake? Some epidemiologists think so. Otis W. Brawley, MD, FACP, Chief Medical & Scientific Officer, American Cancer Society, says: “I really worry when we legislate things that no one understands. People can get harmed.” Numerous issues have to be worked out, according to Brawley. For one, he explains: “There is no standard way to define density.” Additionally, “even though studies suggest that density increases the risk of cancer, these cancers tend to be the less serious kind, but even that is open to question,” Brawley says. “We in medicine do not know what to do for women who have increased density.”

A study of more than 9,000 women in the Journal of the National Cancer Institute revealed that women with very dense breasts were no more likely to die than similar patients whose breasts were not as dense. “When tumors are found later in more dense breasts, they are no more aggressive or difficult to treat,” says Karla Kerlikowske, MD, study coauthor, and professor of medicine and epidemiologist at the University of California San Francisco. In fact, an increased risk of death was only found in women with the least dense breasts.

The trouble is what is known about dense breasts is murky. Asked whether he backs advising women that dense breasts are a risk factor for breast cancer, Anthony B. Miller, MD, Co-Chair of the Cancer Risk Management Initiative and a member of the Action Council, Canadian Partnership Against Cancer, and lead investigator of the Canadian National Breast Cancer Screening Study, says: “I would be very cautious. The trouble is people want certainty and chances are whatever we find, all we can do is explain.”

Women in their forties, who are most likely to have dense breasts (density declines with age) may want to seek out digital mammography. In studies comparing digital mammography to film-screen mammography in the same women, digital mammography has been shown to improve breast cancer detection in women with dense breasts. Findings from the Digital Mammographic Imaging Screening Study, showed better breast cancer detection with digital mammography. But digital mammography is not available in many areas.  Moreover, Miller explains: “We do not know if this will benefit women at all.  It is very probable that removal of the additional small lesions will simply increase anxiety and health costs, including the overdiagnosis of breast cancer, and have no impact upon mortality from breast cancer.”

Additional imaging studies sound attractive to people convinced that there is something clinically significant to find. But as I pointed out in my last post, many radiologists and breast physicians contend that there is no evidence that magnetic resonance imaging or any other imaging study aids breast cancer screening in women with dense breasts. Brawley notes: “These laws will certainly lead to more referral for MRI and ultrasound without clear evidence that women will benefit (lives will be saved.) It’s clear that radiologists will make more money offering more tests.” Miller adds: “A number of doctors are trying to capitalize on this and some of them should know a lot better.”

Many Advocates Question More Tests, Statutes

Even though the “Are You Dense?” campaign has been instrumental in getting legislation on the books across the county, other advocacy groups and patient advocates want research, enhanced patient literacy about risks and benefits of procedures. Many recall mistakes made that led women down the path of aggressive procedures. In that group is the radical Halsted mastectomy, used widely before systematic study, but once studied,  found no better than breast-conserving surgery for many cancers, and bone marrow transplants, also found to be ineffective, wearing, and costly.

Jody Schoger, a breast cancer social media activist at @jodymswho engages women weekly on twitter at #bcsm, had this to say on my blog about the onslaught of additional screening tests:

“What is needed is not another expensive modality… but concentrated focus for a biomarker to indicate the women who WILL benefit from additional screening. Because what’s happening now is an avalanche of screening, and its subsequent emotional and financial costs, that is often far out of proportion to both the relative and absolute risk for invasive cancer. I simply don’t think more “external” technology is the answer but one that evolves from the biology of cancer.”

Eve Harris @harriseve, a proponent of patient navigation and patient literacy, challenged Peter Ubel, MD, professor of business administration and medicine, at Duke University, on his view of the value of patient empowerment on the breast density issue. In a post on Forbes, replicated in Psychology Today, Ubel argued that in cases where the pros and cons of a patient’s alternatives are well known, for example, considering mastectomy or lumpectomy, patient empowerment play an important role. “But we are mistaken to turn to patient empowerment to solve dilemmas about how best to screen for cancer in women with dense breasts,” he writes.

Harris disagrees, making a compelling case for patient engagement:

“I think that we can agree that legislative interference with medical practice is not warranted when it cannot provide true consumer protection. But the context is the biggest culprit in this situation. American women’s fear of breast cancer is out of proportion with its incidence and its mortality rate. Truly empowering people—patients would mean improving health literacy and understanding of risk…”

But evidence and literacy take time, don’t make for snappy reading or headlines, and don’t shore up political points. Can we stop the train towards right-to-inform laws and make real headway in women’s health? Can we reallocate healthcare dollars towards effective treatments that serve patients and engage them in their care? You have to wonder.
[Today’s post is from Patient POVthe blog of Laura Newman, a science writer who has worked in health care for most of her adult life, first as a health policy analyst, and as a medical journalist for the last two decades. She was a proud member of the women’s health movement. She has a longstanding interest in what matters to patients and thinks that patients should play a major role in planning and operational discussions about healthcare. Laura’s news stories have appeared in Scientific American blogs, WebMD Medical News, Medscape, Drug Topics, Applied Neurology, Neurology Today, the Journal of the National Cancer Institute, The Lancet, and BMJ, and numerous other outlets. You can find her on Twitter @lauranewmanny.]

The opinions in this article do not necessarily conflict with or reflect those of the DXS editorial team. 

Mirror Mirror On the Wall, Mirrors Don’t Switch Hands at All

Nearly every kid has asked some variation on the question, “Why do mirrors switch left and right, but not up and down?” Maybe you still ask yourself that question too – it doesn’t seem to make sense. After all, there’s nothing special about “left and right” vs. “up and down” as far as a mirror goes. If you lean sideways, it still looks like your left and right are being switched, leaving your up and down the same.

That’s the clue to solve the mystery: mirrors actually don’t reverse left and right, however it may look. It’s a common misconception – I’ve even seen science museum displays say it. If you really want to see what mirrors do, hold your hand up between your face and the mirror with your palm toward the mirror, so that you can see both your hand and its reflection at the same time. You see the back of your hand, but the reflection shows the palm of your hand, a view you aren’t able to see without the mirror. The mirror is actually reversing front and back! The front of your hand (the side you see without the mirror) is the back of your hand in the reflection.

We can see why mirrors fool us into thinking left and right are swapped, though: it looks like a second person is standing in the mirror, looking back at us. When you raise your right hand, the mirror person appears to raise her left hand. However, what’s really happening is that the mirror person is still raising her right hand, just that the front of your hand is the back of hers, the front of your head is the back of hers, and so forth. If the mirror really flipped left and right, the mirror person would be facing the same way you are: you’d be seeing the back of her head instead of her face!

Concave Mirrors for Makeup and Telescopes

Ordinary bathroom mirrors are flat, but there a kind of mirror that flips left and right as well as front-to-back – but it also reverses up and down, too. This type of mirror is a concave mirror: one like the inside of a polished metal bowl or the cupped part of a soup spoon. Again, you’ve probably played with making faces into a shiny metal spoon: one side gives you an upside-down reflection. (I’ll talk about the other side of the spoon in a little bit – that’s a third kind of mirror.) A spoon is kind of an odd shape, since reflecting your image isn’t their main purpose, but many makeup and shaving mirrors are closer to being ideal concave mirrors.

The upside-down and backward image you see will always appear smaller than you are, but it will also seem to be closer to the mirror than you are. Unless the mirror is nearly flat, your face will appear to be distorted: a big protruding nose and smaller ears fading in the distance. If you sway left, your image will sway right; if you duck down, your image will bob up. That’s how we know the image is truly reversed, unlike the flat mirror! A big concave mirror can be a bit headache-inducing (at least if you’re like me): the image looks very strange compared to the image in your bathroom mirror. That’s because it’s what is known as a real image: it’s on the same side of the mirror as your face, so your eyes have a lot of trouble focusing on it. In fact, if you put a piece of paper at the right location, you can actually project the image from a concave mirror onto it.
There’s a special distance from the mirror known as the focal length, where the light focuses. A very curved mirror has a small focal length, while one that is nearly flat has a large focal length.(Also, the flatter the mirror, the less distortion you see in the image.) If you stand close to the mirror than its focal length, your image will be right-side up and magnified. That’s the real reason many makeup and shaving mirrors are concave: they have large focal lengths, so that your image in the mirror is slightly larger than your actual face – and appears closer to the mirror than your face really is. You can guess the advantage of that: you can see your eyelashes or the contours of your face more clearly.

Let’s go beyond the everyday for a bit: if you want to build a really big telescope, a concave mirror is the way to go. Unlike lenses, you don’t have to make a telescope out of a single flawless piece of glass: you can make a huge metal dish, or make one big mirror out of a bunch of smaller mirrors in a tile pattern. The Keck telescopes in Hawaii are about 30 feet in diameter (actually 10 meters, to be precise): the width of a large classroom or a substantial house! These mirrors focus light onto a detector, creating the wonderful and often beautiful images astronomers use in their work. The huge size of the mirrors allow observatories to see both farther and with higher resolution than smaller telescopes. (If you’re shopping for telescopes, look for words like Newtonian or Cassegrain: those tell you you’re looking at a ‘scope with a mirror rather than lenses.)

You might have a satellite dish; that’s another type of concave mirror, but for radio waves or
microwaves instead of visible light, which is why they don’t look like mirrors at first glance. Again, the purpose is to focus the signal from the satellite. Big radio telescopes are also mirrors: the biggest mirror in the world is the Arecibo radio telescope in Puerto Rico: that one is 1000 feet (305 meters) across!

Objects In Mirror Are
Closer Than They Appear

If you still have your spoon from the previous section (and I hope you do – the author is not responsible for lost utensils), turn it around so that your image appears right-side up. This type of mirror is convex: like the flat mirror, it flips back and front, but not left and right. Like the concave mirror, it distorts your image, but makes your face appear farther away than it really is.

As a quick aside: if you have trouble remembering the difference between “convex” and “concave”, here’s a mnemonic. Concave includes the word “cave”: that’s a
mirror that bows inward. Convex rhymes with “flex”: that’s a mirror that bows outward. At least that’s how I remember which is which!

The passenger-side mirror of a car bears the message “Objects in mirror are closer than they appear”. (Hopefully the object is not a tyrannosaurus.) That mirror is convex, and it’s designed to give a wider view of the side and rear of the car than can be done with a flat mirror. The price of the wider field of vision is that objects do end up looking farther away than they really are. You also see convex mirrors in shops, so that the staff can look down aisles out of their direct vision, and in a famous self-portrait by M.C. Escher.


We’ve come a long way in a short time from a basic flat bathroom mirror: we’ve seen why normal mirrors don’t flip left and right, but why concave mirrors do. We connected
makeup mirrors to the biggest telescopes in the world, and shop mirrors to cars. Even better, you probably have all these types of mirror easily accessible, especially if you’re willing to goof around with spoons. Try them out, see how they work, and the next time someone tells you that mirrors reverse left-to-right, you can help get them facing back the correct way.

Matthew Francis, Double X Science Physics Editor

On Parenting, Science, and Trust

The following was originally posted over at The Mother Geek (RIP) in January of this year.  The guest author is Alice Callahan, who is a research scientist turned stay-at-home mom. She lives in Eugene, Oregon, with her husband and 14-month-old daughter. Alice writes about the science of parenting, as well as her adventures in mothering, at  You can also find Alice on Twitter.
Via Creative Commons

Having a PhD in science makes my job as a mother easier – but maybe not in the ways that you might expect.

My PhD is in Nutrition, so you would think that getting my kid to eat well would come easy for me. Unfortunately, that has not been the case.  I’ve logged more than two years of postdoc research on fetal programming – how the uterine environment affects outcomes in babies. You might think that this helped me to do everything right during my pregnancy. Instead, I think it just led to more worry about all of the ways I might be damaging my unborn child. Stress! Sugar! BPA! Lab chemical exposure! OMG! More stress!
Sure, I have more knowledge than the average mother. Sometimes that is helpful.  And sometimes it is not. And knowing how to do a literature search to try to answer my parenting questions often leads to further sleep deprivation as I slog through Pubmed hits and come out on the other side with more confusion. Sometimes my drive to find scientific answers for my parenting questions just distracts me from my instinct – not that my maternal instinct is all that amazing, but I do know my baby better than anyone else in the world.
So how does being a scientist make parenting easier for me? As a scientist mother, I trust other scientists. And I trust doctors. I even trust government agencies, which bring together the best scientists and doctors in a field to review the research and make recommendations for the good of public health.
I trust scientists and doctors, because I have worked side-by-side with them for a decade, andI know that they are not only knowledgeable,but by and large, they are overwhelmingly good people. At some point, you have to trust someone.

I trust scientists and doctors.   

I trust scientists, because I know that the vast majority of them are just underpaid nerds who are really passionate about what they do. They are driven by the desire to find the truth about a question and they work, day in and day out, in that pursuit.  In addition, I know that scientists don’t always agree, so when there is a general consensus among the majority of scientists about something, such as vaccine safety or global warming, I feel confident in that conclusion.
Contrary to many claims on the Internet, scientists are not in bed with Big Pharma, conspiring make millions at the expense of your child’s health. They are in bed with their husbands and wives, probably chatting about their latest failed cell culture experiment.
I also trust science because I understand the peer review process all too well. Although it has its flaws and as maddening as it is when I am the one being reviewed, I have confidence that the peer review process is highly effective at weeding out the kooks and pseudoscientists and the conflicts of interest. (Unfortunately, there are a few kooky psuedoscientists out there with serious conflicts of interest, and it just so happens that one of them managed to publish fraudulent research linking the MMR vaccine and autism. Many studies have since shown that such a link does not exist, but it took 12 years for Andrew Wakefield’s Lancet paper to be retracted. How many dollars have been spent and how many people made sick or worse in the continuing fallout and confusion about this public health scare? When the peer review system fails, it can be truly devastating.)
I trust doctors because I know that most of them are, first and foremost, humanitarians at heart, especially those that have chosen to work in primary care. I know how hard doctors work to become competent in the vast ocean of information about pathologies of the human body. I know how seriously they take their responsibility of our health.
I especially trust pediatricians. They have chosen one of the lowest-paid specialties simply because they love working with kids. I know that every pediatrician, at some point during her training or career, has likely cared for a child who was dying of a disease that could have been prevented by vaccination, and that memory haunts her as she faces parents afraid of vaccinating their children. Doctors are not conspiring against us. They want to help us make the best choices for our children, more than anything in the world.
Because I trust scientists and doctors, I didn’t question the CDC’s vaccination schedule. I didn’t pore over vaccine research or agonize about the decision to vaccinate my child. Instead, I trusted that the committees of experts at the CDC and AAP carefully make the best recommendations possible based on the data available.
Maybe that is naïve. Maybe I am a lazy mother for not trying to become a vaccine expert before I allowed those first needles to enter my daughter’s thigh. Maybe. But I also think it would be naïve for me to think that I could become an expert on vaccinations, that I could know and understand the field better than the committees of scientists and doctors who have made this their life’s work.
I know how much work it took me to become an expert on one or two corners of nutrition and fetal physiology. It took thousands of hours of reading textbooks and journal articles, sitting in lectures, attending conferences, and struggling at the lab bench before I started to feel even a little bit comfortable calling myself an expert in any field. So I think it is naïve for a parent to think that she can become an expert on vaccines by spending some time on the Internet, reading questionable sources, almost all of which have some agenda. I accept that I can’t know everything, and I have enough faith in humanity that I trust others who know more than me.

It is not that I don’t question scientists and doctors. I do. For example, I recognize that government agencies and medical organizations often have a lag time for adopting the latest science into their recommendations. I recognize that tradition, culture, politics, and economics all influence those recommendations, and they are not without fault.
I certainly question my doctors, because I know they are each fallible human beings, and they can’t know everything. I brought a stack of journal articles to my OB to convince her to delay cord clamping at my delivery. I did so much research on infant iron nutrition and came to my daughter’s 9-month checkup with so many questions that my pediatrician looked me in the eye and said, “You’re worried enough for both of us about BabyC’s iron.” Although I question my doctors, I also trust that they are adept at discerning fake science from real science. If I bring my doctor the sources I am using to inform my questions or concerns, she should be able to judge whether or not they are trustworthy and have a real discussion with me about factors that I may not have considered.
In truth, I do follow the vaccine debate closely, but not because I wonder if I am doing the right thing by vaccinating my child. I follow the vaccine debate out of interest for how misinformation can explode in a way that creates a public health crisis. I find myself increasingly concerned about the low rate of vaccination in my own community. I worry for the newborns in our town who have not yet had a chance to be vaccinated and for the individuals who cannot be vaccinated due to health conditions. I am starting to feel like I have a responsibility to share accurate information with mothers and fathers struggling with the decision of whether or not to vaccinate, because misinformation is doing real harm.

It is good to question our parenting decisions and in doing so, become more educated about them. However, as a scientist, I’m happy to defer to other scientists about some of the biggest parenting decisions I have faced. I am grateful for their decades of research forming the foundation of our understanding of child health and for the good-hearted doctors who care for my family. They have made my job as a mother a lot easier. I can spend less time worrying and more time playing with my daughter and soaking up the time with her as she grows up way too fast.

Thanks, science, for making it easier to be a mom.

These views are the opinion of the author and do not necessarily reflect or disagree with those of the DXS editorial team.

Childbirth and C-sections in pre-modern times

[Today’s post first appeared at Dr. Kristina Killgrove’s blog, Powered by Osteons. Kristina is a bioarchaeologist who studies the skeletons of ancient Romans to learn more about how they lived. Her biography at her blog begins, “When your life’s passion is to study dead Romans, you often get asked for your ‘origin story,’ something that explains a long, abiding and, frankly, slightly creepy love for skeletons.” Now that you undoubtedly want to know more, read the rest of her bio here, and then read below to learn why childbirth is so difficult and what the archaeological record has to tell us about outcomes for mother and child in the ancient world. For more about Kristina and her work, you can see her academic Website at  and find out about her latest research project at You can also find her at her G+ page and on Twitter as @BoneGirlPhD.]

Basically since we started walking upright, childbirth has been difficult for women.  Evolution selected for larger and larger brains in our hominin ancestors such that today our newborns have heads roughly 102% the size of the mother’s pelvic inlet width (Rosenberg 1992).

Yes, you read that right. Our babies’ heads are actually two percent larger than our skeletal anatomy

Fetal head and mother’s pelvic inlet width
Photo credit:

Obviously, we’ve also evolved ways to get those babies out.  Biologically, towards the end of pregnancy, a hormone is released that weakens the cartilage of the pelvic joints, allowing the bones to spread; and the fetus itself goes through a complicated movement to make its way down the pelvic canal, with its skull bones eventually sliding around and overlapping to get through the pelvis.  Culturally, we have another way to deliver these large babies: the so-calledcaesarean section.

Up until the 20th century, childbirth was dangerous.  Even today, in some less developed countries, roughly 1 maternal death occurs for every 100 live births, most of those related to obstructed labor or hemorrhage (WHO Fact Sheet 2010).  If we project these figures back into the past, millions of women must have died during or just after childbirth over the last several millennia.  You would think, then, that the discovery of childbirth-related burial – that is, of a woman with a fetal skeleton within her pelvis – would be common in the archaeological record.  It’s not.

Archaeological Evidence of Death in Childbirth

Two recent articles in the International Journal of Osteoarchaeology start the exact same way, by explaining that “despite this general acceptance of the vulnerability of young females in the past, there are very few cases of pregnant woman (sic) reported from archaeological contexts” (Willis & Oxenham, In Press) and “archaeological evidence for such causes of death is scarce and therefore unlikely to reflect the high incidence of mortality during and after labour” (Cruz & Codinha 2010:491).

The examples of burials of pregnant women that tend to get cited include two from Britain (both published in the 1970s), four from Scandinavia (published in the 1970s and 1980s), three from North America (published in the 1980s), one from Australia (1980s), one from Israel (1990s), six from Spain (1990s and 2000s), one from Portugal (2010), and one from Vietnam (2011) (most of these are cited in Willis & Oxenham).  Additionally, I found some unpublished reports: a skeleton from Egypt, a body from the Yorkshire Wolds in England, and a skeleton from England.

The images of these burials are impressive: even more than child skeletons, these tableaux are pathos-triggering, they’re snapshots of two lives cut short because of an evolutionary trade-off.

The wide range of dates and geographical areas illustrated in the slideshow demonstrates quite clearly that death of the mother-fetus dyad is a biological consequence of being human.  But what we have from archaeological excavations is still fewer than two dozen examples of possible childbirth-related deaths from all of human history.

Where are all the mother-fetus burials?

As with any bioarchaeological question, there are a number of reasons that we may or may not find evidence of practices we know to have existed in the past.  Some key issues at play in recovering evidence of death in childbirth include:
  • Archaeological Theory and Methodology.  From the dates of discovery of maternal-fetal death cited above, it’s obvious that these examples weren’t discovered until the 1970s.  Why the 70s?  It could be that the rise of feminist archaeology focused new attention on the graves of females, with archaeologists realizing the possibility that they would find maternal-fetal burials.  Or it could be that the methods employed got better around this time: archaeologists began to sift dirt with smaller mesh screens and float it for small particles like seeds and fetal bones.
  • Death at Different Times.  Although some women surely perished in the middle of childbirth, along with a fetus that was obstructed, in many cases delivery likely occurred, after which the mother, fetus, or both died.  In modern medical literature, there are direct maternal deaths (complications of pregnancy, delivery, or recovery) and indirect maternal deaths (pregnancy-related death of a woman with preexisting or newly arisen health problems) recorded up to about 42 days postpartum.  An infection related to delivery or severe postpartum hemorraging could easily have killed a woman in antiquity, leaving a viable newborn.  Similarly, newborns can develop infections and other conditions once outside the womb, and infant mortality was high in preindustrial societies.  With a difference between the time of death of the mother and child, a bioarchaeologist can’t say for sure that these deaths were related to childbirth.  Even finding a female skeleton with a fetal skeleton inside it is not always a clear example, as there are forensic cases of coffin birth or postmortem fetal extrusion, when the non-viable fetus is spontaneously delivered after the death of the mother.
  • Cultural Practices.  Another condition of being human is the ability to modify and mediate our biology through culture.  So the final possibility for the lack of mother-fetus burials is a specific society’s cultural practices in terms of childbirth and burial.  In the case of complicated childbirth (called dystocia in the medical literature), this is done through caesarean section (or C-section), a surgical procedure that dates back at least to the origins of ancient Rome.

Cultural Interventions in Childbirth

It’s often assumed that the term caesarean/cesarean section comes from the manner of birth ofJulius Caesar, but it seems that the Roman author Pliny may have just made this up. The written record of the surgical practice originated as the Lex Regia (royal law) with the second king of Rome, Numa Pompilius (c. 700 BC), and was renamed the Lex Caesarea (imperial law) during the Empire.  The law is passed down through Justinian’s Digest (11.8.2) and reads:

Negat lex regia mulierem, quae praegnas mortua sit, humari, antequam partus ei excidatur: qui contra fecerit, spem animantis cum gravida peremisse videtur.

The royal law forbids burying a woman who died pregnant until her offspring has been excised from her; anyone who does otherwise is seen to have killed the hope of the offspring with the pregnant woman. [Translation mine]
Example of Roman gynaecological equipment: speculum
From the House of the Surgeon, Pompeii (1st c AD)
Photo credit: UVa Health Sciences Library

There’s discussion as to whether this law was instituted for religious reasons or for the more practical reason of increasing the population of tax-paying citizens.  In spite of this law, though, there isn’t much historical evidence of people being born by C-section.  Many articles claim the earliest attested C-section as having produced Gorgias, an orator from Sicily, in 508 BC (e.g., Boley 1991), but Gorgias wasn’t actually born until 485 BC and I couldn’t find a confirmatory source for this claim.  Pliny, however, noted that Scipio Africanus, a celebrated Roman general in the Second Punic War, was born by C-section (Historia Naturalis VII.7); if this fact is correct, the earliest confirmation that the surgery could produce viable offspring dates to 236 BC.

This practice in the Roman world is not the same as our contemporary idea of C-section.  That is, the mother was not expected to survive and, in fact, most of the C-sections in Roman times were likely carried out following the death of the mother.  Until about the 1500s, when the French physician François Rousset broke with tradition and advocated performing C-sections on living women, the procedure was performed only as a last-ditch effort to save the neonate.  Some women definitely survived C-sections from the 16th to 19th centuries, but it was still a risky procedure that could easily lead to complications like endometritis or other infection.  Following advances in antibiotics around 1940, though, C-sections became more common because, most importantly, they were much more survivable.

Caesarean Sections and Roman Burials

Roman relief showing a birthing scene
Tomb of a Midwife (Tomb 100), Isola Sacra
Photo credit: magistrahf on Flickr

In spite of the Romans’ passion for recordkeeping, there’s very little evidence of C-sections.  It’s unclear how religiously the Lex Regia/Caesarea was followed in Roman times, which means it’s unclear how often the practice of C-section occurred.  Would all women have been subject to these laws?  Just the elite or just citizens?  How often did the section result in a viable newborn?  Who performed the surgery?  It probably wasn’t a physician (since men didn’t generally attend births), but a midwife wouldn’t have been trained to do it either (Turfa 1994).

Whereas we can supplement the historical record with bioarchaeological evidence to understand Romans’ knowledge of anatomy, their consumption of lead sugar, or the practice of crucifixion, this isn’t possible with C-sections – the surgery is done in soft tissue only, meaning we’d have to find a mummy to get conclusive evidence of an ancient C-section.

We can make the hypothesis, though, that because of the Lex Regia/Caesarea, we should findno evidence in the Roman world of a woman buried with a fetus still inside her.  This hypothesis, though, is quickly negated by two reported cases – one from Kent in the Romano-British period and one from Jerusalem in the 4th century AD. The burial from Kent hasn’t been published, although there is a photograph in the slide show above.

Interestingly, the Jerusalem find was studied and reported by Joe Zias, who also analyzed theonly known case of crucifixion to date.  Zias and colleagues report on the find in Nature(1993) and in an edited volume (1995), but their primary goal was to disseminate information about the presence of cannabis in the tomb (and its supposed role in facilitating childbirth), so there’s no picture and the information about the skeletons is severely lacking:

We found the skeletal remains of a girl (sic) aged about 14 at death in an undisturbed family burial tomb in Beit Shemesh, near Jerusalem.  Three bronze coins found in the tomb dating to AD 315-392 indicate that the tomb was in use during the fourth century AD.  We found the skeletal remains of a full-term (40-week) fetus in the pelvic area of the girl, who was lying on her back in an extended position, apparently in the last stages of pregnancy or giving birth at the time of her death… It seems likely that the immature pelvic structure through which the full-term fetus was required to pass was the cause of death in this case, due to rupture of the cervix and eventual haemorrhage (Zias et al. 1993:215).

Both Roman-era examples involve young women, and it is quite interesting that they were already fertile.  Age at menarche in the Roman world depended on health, which in turn depended on status, but it’s generally accepted that menarche happened around 14-15 years old and that fertility lagged behind until 16-17, meaning for the majority of the Roman female population, first birth would not occur until at least 17-19 years of age (Hopkins 1965, Amundsen & Diers 1969).  These numbers have led demographers like Tim Parkin (1992:104-5) to note that pregnancy was likely not a major contributor to premature death among Roman women.  But the female pelvis doesn’t reach skeletal maturity until the late teens or early 20s, so complications from the incompatibility in pelvis size versus fetal head size are not uncommon in teen pregnancies, even today (Gilbert et al. 2004).

More interesting than the young age at parturition is the fact that both of these young women were likely buried with their fetuses still inside them, in direct violation of the Lex Caesarea.  So it remains unclear whether this law was ever prosecuted, or if the application of the law varied based on location (these young women were both from the provinces), social status (both young women were likely higher status), or time period.  Why wasn’t medical intervention, namely C-section, attempted on these young women?  It’s possible that further context clues from the cemeteries and associated settlements could give us more information about medical practices in these specific locales, but neither the Zias articles nor the Kent report make this information available.

Childbirth – Biological or Cultural?

Childbirth is both a biological and a cultural process.  While biological variation is consistent across all human populations, the cultural processes that can facilitate childbirth are quite varied.  The evidence that bioarchaeologists use to reconstruct childbirth in the past includes skeletons of mothers and their fetuses; historical records of births, deaths, and interventions; artifacts that facilitate delivery; and context clues from burials.  The brief case study of death in childbirth in the Roman world further shows that history alone is insufficient to understand the process of childbirth, the complications inherent in it, and the form of burial that results.  In order to develop a better understanding of childbirth through time, it’s imperative that archaeologists pay close attention when excavating graves, meticulously document their findings, and publish any evidence of death in childbirth.

Further Reading:

This post was chosen as an Editor's Selection for ResearchBlogging.orgD.W. Amundsen, & C.J. Diers (1969). The age of menarche in Classical Greece and Rome. Human Biology, 41 (1), 125-132. PMID: 4891546.

J.P. Boley (1991). The history of caesarean section. Canadian Medical Association Journal, 145 (4), 319-322. [PDF]

S. Crawford (2007). Companions, co-incidences or chattels? Children in the early Anglo-Saxon multiple burial ritual.  In Children, Childhood & Society, S. Crawford and G. Shepherd, eds.  BAR International Series 1696, Chapter 8. [PDF]

C. Cruz, & S. Codinha (2010). Death of mother and child due to dystocia in 19th century Portugal. International Journal of Osteoarchaeology, 20, 491-496. DOI: 10.1002/oa.1069.

W. Gilbert, D. Jandial, N. Field, P. Bigelow, & B. Danielsen (2004). Birth outcomes in teenage pregnancies. Journal of Maternal-Fetal and Neonatal Medicine, 16 (5), 265-270. DOI:10.1080/14767050400018064.

K. Hopkins (1965). The age of Roman girls at marriage. Population Studies, 18 (3), 309-327. DOI: 10.2307/2173291.

E. Lasso, M. Santos, A. Rico, J.V. Pachar, & J. Lucena (2009). Postmortem fetal extrusion. Cuadernos de Medicina Forense, 15 (55), 77-81. [HTML – Warning: Graphic images!]

T. Parkin (1992).  Demography and Roman society.  Baltimore: Johns Hopkins University Press.

K. Rosenberg (1992). The evolution of modern human childbirth. American Journal of Physical Anthropology, 35 (S15), 89-124. DOI: 10.1002/ajpa.1330350605
J.M. Turfa (1994). Anatomical votives and Italian medical traditions. In: Murlo and the Etruscans, edited by R.D. DePuma and J.P. Small. University of Wisconsin Press.

C. Wells (1975). Ancient obstetric hazards and female mortality. Bulletin of the New York Academy of Medicine, 51 (11), 1235-49. PMID: 1101997.

A. Willis, & M. Oxenham (In press). A Case of Maternal and Perinatal Death in Neolithic Southern Vietnam, c. 2100-1050 BCE. International Journal of Osteoarchaeology, 1-9. DOI:10.1002/oa.1296.

J. Zias, H. Stark, J. Seligman, R. Levy, E. Werker, A. Breuer & R. Mechoulam (1993). Early medical use of cannabis. Nature, 363 (6426), 215-215. DOI: 10.1038/363215a0.

J. Zias (1995). Cannabis sativa (hashish) as an effective medication in antiquity: the anthropological evidence. In: S. Campbell & A. Green, eds., The Archaeology of Death in the Ancient Near East, pp. 232-234.

Note: Thanks to Marta Sobur for helping me gain access to the Zias 1995 article, and thanks toSarah Bond for helping me track down the Justinian reference.

Don’t worry so much about being the right type of science role model

Role models: How do they look? (Source)
[Today we have a wonderful guest post from Marie-Claire Shanahan, continuing the conversation about what makes someone a good role model in science. This post first appeared at Shanahan’s science education blog, Boundary Vision, and she has graciously agreed to let us share it here, too. Shanahan is an Associate Professor of Science Education and Science Communication at the University of Alberta where she researches social aspects of science such as how and why students decide to pursue science degrees. She teaches courses in science teaching methods, scientific language and sociology of science. Marie-Claire is also a former middle and high school science and math teacher and was thrilled last week when one of her past sixth grade students emailed to ask for advice on becoming a science teacher. She blogs regularly about science education at Boundary Vision and about her love of science and music at The Finch & Pea.]

What does it mean to be a good role model? Am I a good role model? Playing around with kids at home or in the middle of a science classroom, adults often ask themselves these questions, especially when it come to girls and science. But despite having asked them many times myself, I don’t think they’re the right questions.

Studying how role models influence students shows a process that is much more complicated than it first seems. In some studies, when female students interact with more female professors and peers in science, their own self-concepts in science can be improved [1]. Others studies show that the number of female science teachers  at their school seems to have no effect [2].

Finding just the right type of role model is even more challenging. Do role models have to be female? Do they have to be of the same race as the students? There is often an assumption that even images and stories can change students’ minds about who can do science. If so, does it help to show very feminine women with interests in science like the science cheerleaders? The answer in most of these studies is, almost predictably, yes and no.

Diana Betz and Denise Sekaquaptewa’s recent study “My Fair Physicist: Feminine Math and Science role models demotivate young girls” seems to muddy the waters even further, suggesting that overly feminine role models might actually have a negative effect on students. [3] The study caught my eye when PhD student Sara Callori wrote about it and shared that it made her worry about her own efforts to be a good role model.

Betz and Sekaquaptewa worked with two groups of middle school girls. With the first group (144 girls, mostly 11 and 12 years old) they first asked the girls for their three favourite school subjects and categorized any who said science or math as STEM-identified (STEM: Science, Technology, Engineering and Math). All of the girls then read articles about three role models. Some were science/math role models and some were general role models (i.e., described as generally successful students). 

The researchers mixed things even further so that some of the role models were purposefully feminine (e.g., shown wearing pink and saying they were interested in fashion magazines) and others were supposedly neutral (e.g., shown wearing dark colours and glasses and enjoying reading).* There were feminine and neutral examples for both STEM and non-STEM role models. After the girls read the three articles, the researchers asked them about their future plans to study math and their current perceptions of their abilities and interest in math.**

For the  most part, the results were as expected. The STEM-identified girls showed more interest in studying math in the future (not really a surprise since they’d already said math and science were their favourite subjects) and the role models didn’t seem to have any effect. Their minds were, for the most part, already made up.

What about the non-STEM identified girls, did the role models help them? It’s hard to tell exactly because the researchers didn’t measure the girls’ desire to study math before reading about the role models.  It seems though that reading about feminine science role models took away from their desire to study math both in the present and the future. Those who were non-STEM identified and read about feminine STEM role models rated their interest significantly lower than other non-STEM identified girls who read about neutral STEM role models and about non-STEM role models. A little bit surprising was the additional finding that the feminine role models also seemed to lower STEM-identified girls current interest in math (though not their future interest).

The authors argue that the issue is unattainability. Other studies have shown that role models can sometimes be intimidating. They can actually turn students off if they seem too successful, such that their career or life paths seem out of reach, or if students can write them off as being much more talented or lucky than themselves. Betz and Sekaquaptewa suggest that the femininity of the role models made them seem doubly successful and therefore even more out of the students’ reach.

The second part of the study was designed to answer this question but is much weaker in design so it’s difficult to say what it adds to the discussion. They used a similar design but with only the STEM role models, feminine and non-feminine (and only 42 students, 20% of whom didn’t receive part of the questionnaire due to an error). The only difference was instead of asking about students interest in studying math they tried to look at the combination of femininity and math success by asking two questions:

  1. “How likely do you think it is that you could be both as successful in math/science AND as feminine or girly as these students by the end of high school?” (p. 5)
  2. “Do being good at math and being girly go together?” (p. 5)

Honestly, it’s at this point that the study loses me. The first question has serious validity issues (and nowhere in the study is the validity of the outcome measures established). First, there are different ways to interpret the question and for students to decide on a rating. A low rating could mean a student doesn’t think they’ll succeed in science even if they really want to. A low rating could also mean that a student has no interest in femininity and rejects the very idea of being successful at both. These are very different things and make the results almost impossible to interpret. 

Second these “successes” are likely different in kind. Succeeding in academics is time dependent and it makes sense to ask young students if they aspire to be successful in science. Feminine identity is less future oriented and more likely to be seen as a trait rather a skill that is developed. It probably doesn’t make sense to ask students if they aspire to be more feminine, especially when femininity has been defined as liking fashion magazines and wearing pink.

Question: Dear student, do you aspire to grow up to wear more pink? 

Answer (regardless of femininity): Um, that’s a weird question.

With these questions, they found that non-STEM identified girls rated themselves as unlikely to match the dual success of the feminine STEM role models. Because of the problems with the items though, it’s difficult to say what that means. The authors do raise an interesting question about unattainability, though, and I hope they’ll continue to look for ways to explore it further.

So, should graduate students like Sara Callori be worried? Like lots of researchers who care deeply about science, Sara expressed a commendable and strong desire to make a contribution to inspiring young women in physics (a field that continues to have a serious gender imbalance). She writes about her desire to encourage young students and be a good role model:

When I made the decision to go into graduate school for physics, however, my outlook changed. I wanted to be someone who bucked the stereotype: a fashionable, fun, young woman who also is a successful physicist. I thought that if I didn’t look like the stereotypical physicist, I could be someone that was a role model to younger students by demonstrating an alternative to the stereotype of who can be a scientist. …This study also unsettled me on a personal level. I’ve long desired to be a role model to younger students. I enjoy sharing the excitement of physics, especially with those who might be turned away from the subject because of stereotypes or negative perceptions. I always thought that by being outgoing, fun, and yes, feminine would enable me to reach students who see physics as the domain of old white men. These results have me questioning myself, which can only hurt my outreach efforts by making me more self conscious about them. They make me wonder if I have to be disingenuous about who I am in order to avoid being seen as “too feminine” for physics.

To everyone who has felt this way, my strong answer is: NO, please don’t let this dissuade you from outreach efforts. Despite results like this, when studies look at the impact of role models in comparison to other influences, relationships always win over symbols. The role models that make a difference are not the people that kids read about in magazines or that visit their classes for a short period of time. The role models, really mentors, that matter are people in students’ lives: teachers, parents, peers, neighbours, camp leaders, and class volunteers. And for the most part it doesn’t depend on their gender or even their educational success. What matters is how they interact with and support the students. 
Good role models are there for students, they believe in their abilities and help them explore their own interests.

My advice? Don’t worry about how feminine or masculine you are or if you have the right characteristics to be a role model, just get out there and get to know the kids you want to encourage. Think about what you can do to build their self-confidence in science or to help them find a topic they are passionate about. When it comes to making the most of the interactions you have with science students, there are a few tips for success (and none of them hinge on wearing or not wearing pink):

§   Be supportive and encouraging of students’ interest in science. Take their ideas and aspirations seriously and let them know that you believe in them. This turns out to be by far one of the most powerful influences in people pursuing science. If you do one thing in your interactions with students, make it this.

§  Share with students why you love doing science. What are the benefits of being a scientist such as contributing to improving people’s lives or in solving difficult problems? Students often desire careers that meet these characteristics of personal satisfaction but don’t always realize that being a scientist can be like that.

§  Don’t hide the fact that there are gender differences in participation in some areas of science (especially physics and engineering). Talk honestly with students about it, being sure to emphasize that differences in ability are NOT the reason for the discrepancies. Talk, for example, about evidence that girls are not given as many opportunities to explore and play with mechanical objects and ask them for their ideas about why some people choose these sciences and others don’t.
There are so many ways to encourage and support students in science, don’t waste time worrying about being the perfect role model. If you’re genuinely interested in taking time to connect with students, you are already the right type.

* There are of course immediate questions about how well supported these are as feminine characteristics but I’m willing to allow the researchers that they could probably only choose a few characteristics and had to try to find things that would seem immediately feminine to 11-12 year olds. I still think it’s a shallow treatment of femininity, one that disregards differences in cultural and class definitions of femininity. (And I may or may not still be trying to sort out my feelings about being their gender neutral stereotype, says she wearing grey with large frame glasses and a stack of books beside her).

**The researchers unfortunately did not distinguish between science and math, using them interchangeably despite large differences in gender representation and connections to femininity between biological sciences, physical sciences, math and various branches of engineering.

[1] Stout, J. G., Dasgupta, N., Hunsinger, M., & McManus, M. A. (2011). STEMing the tide: Using ingroup experts to inoculate women’s self-concept in science, technology, engineering, and mathematics (STEM).Journal of Personality and Social Psychology, 100, 255-270.

[2] Gilmartin, S., Denson, N., Li, E., Bryant, A., & Aschbacher, P. (2007). Gender ratios in high school science departments: The effect of percent female faculty on multiple dimensions of students’ science identities.Journal of Research in Science Teaching, 44, 980–1009.

[3] Betz, D., & Sekaquaptewa, D. (2012). My Fair Physicist? Feminine Math and Science Role Models Demotivate Young Girls Social Psychological and Personality Science DOI: 10.1177/1948550612440735

Further Reading

Buck, G. A., Leslie-Pelecky, D., & Kirby, S. K. (2002). Bringing female scientists into the elementary classroom: Confronting the strength of elementary students’ stereotypical images of scientists. Journal of Elementary Science Education, 14(2), 1-9.

Buck, G. A., Plano Clark, V. L., Leslie-Pelecky, D., Lu, Y., & Cerda-Lizarraga, P. (2008). Examining the cognitive processes used by adolescent girls and women scientists in identifying science role models: A feminist approach. Science Education, 92, 2–20.

Cleaves, A. (2005). The formation of science choices in secondary school.International Journal of Science Education, 27, 471–486.

Ratelle, C.F., Larose, S., Guay, F., & Senecal, C. (2005). Perceptions of parental involvement and support as predictors of college students’ persistence in a science curriculum. Journal of Family Psychology, 19, 286–293.

Simpkins, S. D., Davis-Kean, P. E., & Eccles, J. S. (2006). Math and science motivation: A longitudinal examination of the links between choices and beliefs. Developmental Psychology, 42, 70–83.

Stout, J. G., Dasgupta, N., Hunsinger, M., & McManus, M. (2011). STEMing the tide: Using ingroup experts to inoculate women’s self-concept and professional goals in science, technology, engineering, and mathematics (STEM). Journal of Personality and Social Psychology, 100,255–270.