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The Nature of Breasts

The modern world lays siege to a miracle of evolutionary engineering

Breasts: A Natural and Unnatural History

Florence Williams

Norton, 352pp., $25.95

In 2005, Florence Williams was a working, not-so-young mother with two little kids, Annabel and Ben. Having imbibed, as it were, the message "Breast Is Best," Williams was still nursing Annabel, then a year old, which meant that she was also carefully monitoring her own intake -- lots of vitamins and organic produce, minimal alcohol and caffeine. But even as Williams was trying to safeguard Annabel, she kept coming across headlines that made her anxious. One in 17 women had enough mercury in her blood to risk causing learning disabilities in her children. The Environmental Protection Agency expressed concern that even low-level exposure to perfluorooctanoic acid, used in the manufacture of Teflon, could potentially lead to developmental problems. Flame retardants known as PBDEs, which were known to cause brain damage in rats, were increasingly showing up in human breast milk.

"Had I been wrong to be so smug about the superiority of breast-feeding?" Williams wondered.

As a journalist, Williams realized that her own experience was a story. (She is a contributing editor at Outside magazine and also a contributor to OnEarth.) She decided to have her breast milk analyzed and sent vials of frozen milk off to Germany. While she awaited the results, she learned more: in Sweden, levels of PBDEs in breast milk had been doubling every five years since the early 1970s. In American women, these levels are now 10 to 100 times higher than in women in Europe or Japan. PBDEs are everywhere: in chicken, pork, and dairy products; in wild birds; in soil sediments; in human fetal tissue.

Williams’s test results eventually came back right around normal for an American, which is to say elevated. Presumably her levels had been even higher before she nursed her two kids, to whom she might have unwittingly bequeathed about half of her body’s accumulated PBDEs. Williams wrote up her findings for the New York Times Magazine, which ran the piece under the anxiety-producing headline "Toxic Breast Milk?"

Though her daughter soon afterward stopped nursing, Williams’s interest in breastfeeding -- and breasts more generally -- persisted. The result is Breasts: A Natural and Unnatural History, a lively and informative look at the most-ogled but in many ways least understood part of the human body. By turns funny and scary, Breasts takes up issues that concern all of us in the most intimate possible ways, whether or not we have a pair of our own.

The ability to nurse is, of course, a defining characteristic of mammals, one that female humans share with distaff monkeys, rodents, and tenrecs. But only humans have breasts as we know them -- "pleasant orbs," as Williams puts it, that stick around (and also out) "regardless of our reproductive status." The first question Williams takes up is: Why? The quest takes her all the way to New Zealand, where she interviews Alan and Barnaby Dixson, a father-and-son academic team whose research consists of showing men pictures of naked women. The Dixsons belong to what might be called the "how to marry a caveman" school. They believe that human breasts evolved to signal sexual fitness. Opposed to them are researchers like the anthropologist Frances Mascia-Lees, of Rutgers University, who argue that human breasts serve the far less titillating purpose of energy storage. According to Mascia-Lees, breasts are merely the "by-products of fat deposition."

Williams never resolves the dispute between the two groups. This isn’t a knock on her reporting; at this point at least, the answer isn’t known. The same holds true for a lot of other questions about breasts. As Williams points out, "there have been, and continue to be, big gaps in our knowledge about how these organs work."

Take, for instance, the question of puberty. In the Western world, girls seem to be developing breasts earlier and earlier. A 1997 study put the average age at 10 years for white girls and 8.9 for African-Americans. In 1999 the official age for "precocious puberty" was revised down, from 8 years to 7 for white girls and from 7 to 6 for African-Americans. Meanwhile, a Danish study conducted in 2006 found that girls were budding breasts a full 12 months earlier than they had just 15 years before. The trend is not just disconcerting but  also dangerous: early puberty has been shown to increase the risk of breast cancer.

So what’s going on here? One theory blames fat; as teens and preteens have put on weight, the age of puberty has advanced. But weight gain, it turns out, can’t fully explain the change. Something else must be going on as well. Girls these days, and of course boys as well, are exposed to a fantastic array of hormone-disrupting chemicals. These include, in addition to PBDEs, phthalates, bisphenol A, organochlorine pesticides, and industrial solvents. Some of these chemicals, ironically enough, are found in personal care products, such as shampoos and toothpaste. "One lesson," Williams writes, "is that the 'cleaner' you are -- at least by the standards of consumer culture -- the more contaminated you are." But no one knows which, if any, of the compounds is the culprit, or how exactly it might be affecting the age of puberty. "What is scary is that we don’t have any idea what the mechanism is," a Danish scientist tells Williams.

Breasts makes several forays into what might be called the cultural anthropology of the bust. One chapter, for instance, explores the appeal of the boob job, a research effort that takes Williams to the offices of Michael Ciaravino, a plastic surgeon in Houston who performs some 800 breast augmentation operations a year. But the book’s major focus is on health, and though Breasts is obviously catchier than Cancers of the Breast, the latter title speaks to the focus of much of Williams’s book. In the United States, she points out, the incidence of breast cancer has been rising by between 1 percent and 2 percent a year for at least half a century. In the year 1940, the number of women diagnosed with the disease was 59 out of 100,000; today it’s more than double that.

Among men, too, the incidence is rising. As it happens, Camp Lejeune, a Marine Corps base in North Carolina, has produced the largest cluster of male breast cancer sufferers ever identified. The cluster seems to be connected to the camp’s water supply, which for many years was heavily contaminated with benzene, trichloroethylene, and perchloroethylene -- all known or probable human carcinogens.

In one particularly moving chapter, Williams interviews some of the members of the cluster. Michael Partain, who was conceived and born at Camp Lejeune, found out that he had breast cancer at age 39. He suspects in utero exposure. "It’s every woman’s worst nightmare, that something they can do when they’re pregnant can affect their unborn child," he says. "I saw it in my mother’s eyes, the most heartbreaking look, despair."

It is hoped that research on the cluster will finally demonstrate the links between certain types of breast cancer and certain classes of chemicals, links that so far have remained elusive. "From an academic point of view, it’s good," one researcher observes. "For the men involved, it’s terrible."

Williams is a graceful writer, and the story she has to tell is an important one. That, in the end, many of the questions she raises can’t be answered turns out, in itself, to be revelatory. Over and over again, we’ve released chemicals into our air, water, and food supply -- DDT, PCBs, CFCs -- only to learn that we’ve made a terrible mistake. You might think we’d wise up and demand rigorous testing of new compounds before they enter general use. But 50 years after the publication of Rachel Carson’s Silent Spring, Williams notes, "In the United States, every chemical is assumed safe until proved guilty." The untested compounds build up in our own bodies, and then we pass them on to our kids. Of course, no mother wants to harm her children, which is why parents can be such a potent force for change. "When breast milk speaks, people listen," one researcher tells Williams. Let’s hope they are listening to Breasts.

image of Elizabeth Kolbert
Elizabeth Kolbert is a staff writer at the New Yorker and author of Field Notes From a Catastrophe: Man, Nature, and Climate Change. Her next book, The Sixth Extinction: An Unnatural History, will be released in February 2014.
We love it that the author is using a picture of the Onofre nuclear power plant domes, which look suspiciously like a pair of breasts, to promote her book off her facebook page!