"The primary biological function of breasts," wrote humorist Dave Barry, "is to make males stupid."

Well, not exactly, though, in fact, some studies have suggested just that. In Breasts: A Natural and Unnatural History, environmental journalist Florence Williams takes the reader on a journey that's "part biology, part anthropology, part medical journalism." Along the way, Williams explores little-discussed aspects of the fascinating organs that are unique to mammals, giving our taxonomic class its name ("breasts are us" Williams quips), yet being in their relative permanence unique to humans. (In other mammalian species, breasts show up at the end of pregnancy and hang around, so to speak, only until weaning is completed. We're the only ones who get to keep them from puberty onward.)

Unexpectedly, a major concern of the book is environmental: breasts, it seems, are highly sensitive, acting a little like antennae by absorbing not only information from their environment but chemicals, too: the mammary gland is "the most sensitive organ to known harmful industrial chemicals." Substances like BPA—which appears in the lining of food cans and in most polycarbonate (#7) plastics—activate the estrogen receptors on breast cells, causing all kinds of problems, including increased rates of breast cancer and a lowering of the age of puberty. Fifty percent of girls in the U.S. now have breasts—or the beginnings thereof—by age ten, a phenomenon that's pretty unusual in the long view of human history and that's socially problematic: our daughters are reaching physical puberty well before they reach emotional and cognitive maturity.

(Boys and men are not off the hook either; phthalates and BPA function not only as estrogen-copycats but as anti-androgens, and have been linked to smaller penises, lower sperm counts, and other physical markers of feminization in boys. Is Mark Driscoll about to get on the BPA-banning bandwagon? We can only hope.)

That breast tissue is so sensitive to industrial chemicals is troubling, and not only for women. At the Marine Corps Base Camp Lejeune, the drinking and bathing water was for many years contaminated with industrial chemicals like degreasers and dry-cleaning solvents; Breasts has a picture of a tough-looking old Marine grimly saluting the camera, his right-side mastectomy fully visible. Williams explores the various research on breast cancer prevention and early detection, even purchasing a "tactually accurate" silicone breast to learn how better to perform breast self examinations (BSEs), which, for women at high risk for breast cancer, are better than mammography. ("My best advice to you, dear reader? Know thy breasts.")

But I think the part of Breasts that affected me most deeply was the part that talks about breastmilk and how breasts make it. Williams manages not to sound militant as she leads us through the wonders of breastfeeding, freely confessing her own early breastfeeding struggles. She gives a mini-history of La Leche League (they formed in an era when even doctors thought breastmilk was potentially "dirty" and dangerous, formula feeding being cleaner and more "scientific") and explores the protective benefits of lactation not only for babies (it helps colonize their guts with good bacteria) but for mamas (it significantly reduces the risk of breast cancer.) And yet there's this: Williams sent her breastmilk to Germany to be tested for flame retardants and other industrial chemicals. Her chemical levels came back ten to a hundred times higher than those of the average European woman; her breastmilk was found to contain perchlorate, a jet-fuel ingredient, "which certainly is not what baby has in mind for dinner." "Our breasts," she writes, "soak up pollution like a pair of soft sponges"; they are "the catchment for our environmental trespasses." And they pass those on to the next generation, too.

No "natural and unnatural" history of breasts would be complete without a discussion of implants, and Williams doesn't shirk there, either. In good investigative style, she submits to an embarrassing exam and a session in an imaging machine that shows what she'd look like with her breasts inflated a few cup sizes ("va-va-va-voom, and not in a good way"); she also observes a breast-enhancement surgery. The cultural value afforded to larger breasts is such that despite the danger and decreased sensation that accompanies breast surgery, most women with implants describe themselves as happy with them.

Williams' account of the evolution of the breast can be read, by those with a mind to do so, as a tribute to endlessly unfolding creation, and indeed she celebrates eloquently graceful design wherever she finds it—in breasts and in the brains of those who study them, and even in baby poop (one researcher cultures breastfed baby poo to learn about the powerful immunities conferred by breastmilk). We are connected to creation as deeply and intimately as the tree in Joyce Kilmer's poem ("a tree whose hungry mouth is prest / Against the sweet earth's flowing breast"). Williams' book is yet another reminder that caring for creation is caring for people—and, from the looks of things, for women and children first: "[W]hen we became aware of chemicals in breastmilk," she writes, "a powerful new lobby of mothers helped sweep DDT and PCBS off the marketplace. The same fate will likely befall brominated flame retardants. But for scores of other chemicals, the science is young and the regulators often stripped of meaningful power."

For the sake of our most vulnerable organs—and our most vulnerable people—God's creation deserves better.

Rachel Marie Stone lives in Greenport, New York. She blogs on food and faith at rachelmariestone.com. Her book, Eat with Joy: Redeeming God's Gift of Food, is forthcoming from InterVarsity Press in 2013.

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