Reaching Puberty Early

Environmental factors are putting Black girls at risk.

By Susan H. Shane Jul 01, 2008

Ed note: This essay was published in the July/August 2008 print edition of ColorLines magazine.

JUST AFTER MY DAUGHTER TURNED 7, she came to me and nervously announced that she had bumps on her chest. I felt beneath her nipples, and, indeed, there were prominent, hard lumps. A friend had gone through this with her 7-year-old, so my first fleeting panic about cancer was replaced by the alarming realization that my little girl was developing breasts. I made an appointment with our family doctor, but it was two weeks off.

In the meantime, I googled "premature puberty" and discovered the literature on environmental causes of early puberty. I also found that family history, prenatal and early postnatal exposures were key. I had adopted my daughter when she was 3 months old. While I knew she’d never been breastfed, I knew little else about her history or that of her birthmother. I set out to find out everything I could about early puberty in girls, trolling through the medical literature, gleaning library shelves, exploring the websites of environmental organizations and conversing with scientists who are grappling with this issue.

Why was I so alarmed about my Black daughter starting puberty at the age of 7? As a white mom who first menstruated at 13, I was afraid of the prospect of my child dealing with sexuality at such a young age. My fear increased as I found studies showing a litany of social risks for girls who mature early: poor self-esteem, increased depression, early sexual intercourse and increased drug and alcohol use and abuse. Most worrisome to me were the increased health risks associated with early puberty: breast cancer, type II diabetes, cardiovascular disease and polycystic ovarian syndrome. Early-maturing girls reach their adult height early, and if this occurs by age 12, they have a significant risk of getting a very aggressive form of breast cancer. I knew that I had to take action.

One of the first discoveries I made was that girls were having different experiences with puberty based on race. A 1997 study, conducted at pediatricians’ offices nationwide, found that girls were showing the first signs of puberty about a year earlier than was considered normal. Most striking was that Black girls were beginning puberty about a year earlier than white girls. Compared with 8-year-old white girls, about four times as many Black 8-year-olds grow pubic hair and develop breast buds. The age when girls get their first periods has also dropped (though less dramatically) over the past 30 years, and Black girls precede white girls by half a year in this regard.

Dr. Paul Kaplowitz of the Children’s National Medical Center in Washington, D.C., has suggested that genetic differences between Black and white people may explain early puberty in Black girls. He wonders if the genes involved in insulin resistance, which occurs more often in Black people, may predispose Black girls to earlier puberty by affecting their hormone levels. However, in 1944, girls of both races started puberty at the same age. Today, girls from well-off Black families in South Africa and Cameroon get their first periods at least one year later than Black girls in the United States, and Kenyan Black girls menstruate four years later, on average, than Black girls here.

Doctors have suggested that the dramatic rise in childhood obesity has contributed to earlier puberty. We know that being fat increases the estrogen in a girl’s body, and estrogen is the chief trigger for breast budding. At every age, the percentage of Black girls who are overweight is significantly higher than that of white girls. However, researchers have concluded that, while obesity plays a role, it is not the only cause of early puberty. My daughter, for example, is very thin, so obesity wasn’t even a possible culprit in her case.

When I began looking into environmental causes, however, a clearer picture began forming. Dr. Sandra Steingraber, author of the Breast Cancer Fund’s comprehensive 2007 report "The Falling Age of Puberty in U.S. Girls" considers early puberty to be "an ecological disorder" resulting from a complex web of environmental influences. Pollutants, plastics and chemicals may be the hidden causes of early puberty in girls, and Black girls seem to be more vulnerable.


When I discovered my daughter’s breast buds, I emptied my house of plastic water bottles and stopped letting her eat school lunches that are heated in plastic. I did this just on a hunch. With great relief, I watched her breast buds recede over the next month. In fact, by the time she saw the doctor two weeks later, her breast buds had shrunk to the point that he was unimpressed. A friend whose daughter sprouted pubic hair at the age of 6 and a half tossed out all of the plastic in her house and had the satisfaction of watching the pubic hair vanish.

These anecdotes are not backed by hard statistics, because studies in this area have yet to be prioritized, but they fit perfectly with what we’ve recently learned about plastics.

Polycarbonate plastics (imprinted with a number 7) are made hard and durable by bisphenol A, or BPA, one of the most abundant synthetic chemicals nowadays. More than six billion pounds of BPA are produced in the United States each year. It is in so many products that it is impossible to name them all, but they include dental sealants and fillings, some food containers, 80 percent of food can liners and many water bottles. BPA also leaches from landfills into groundwater and is found in indoor air. A 2008 report by the Centers for Disease Control showed that 93 percent of people randomly tested had BPA in their urine, but the highest levels were found in Blacks, women, young children and poor people.

Most baby bottles are made of polycarbonate plastic. It turns out that 3.5 ppb (parts per billion) of BPA leach into milk from new baby bottles and eight times that much from worn and heated bottles. Black babies are primarily bottle-fed–only 5 percent of Black women breastfeed exclusively for the first six months of their babies’ lives, as the World Health Organization recommends. Poor Black women, in particular, are discouraged from breastfeeding by the free formula dispensed by the Women Infants and Children (WIC) program.

Last year, the federal government sponsored a gathering of 38 medical researchers to determine what effects BPA has on humans. The group reported that BPA acts the same way in humans as it does in animals and the levels in humans are causing negative health effects. It’s possible that BPA might be contributing to our obesity epidemic, which is already tied to early puberty. Most relevant to us: the scientists concluded that early puberty is directly linked to low-dose exposure to BPA.
Another group of synthetic chemicals, used to make plastic flexible, has been linked to early breast budding in girls. These chemicals, called phthalates, are used to make polyvinyl chloride, or PVC, (identified by a number 3) which is what many water pipes are made of. They’re also found in food wrappings, the lining of cardboard boxes that hold liquid or fatty foods, medical tubing, time-release capsules, kids’ toys, insect repellents and countless personal care products. This last category includes shampoo, lotions and deodorants. The CDC found that phthalates compose up to 3 percent of some of these products. Women of childbearing age are the group most exposed to phthalates.

Another way we’re exposed to hormones, of course, is through our diet. There are six sex and growth hormones permitted by the Food and Drug Administration in commercial beef cattle. When people eat beef, they are adding these hormones to their systems. No one knows if eating commercially produced beef plays a role in early puberty, but suspicion is warranted.


Black people suffer disproportionately compared with whites in most measures of health in the United States, and very early puberty in Black girls joins this alarmingly long list. Every risk factor for early puberty affects Black girls more than white girls.

One way that Black girls are exposed to even more chemicals than white girls, though, is through the heavy use of hair care products. In 1998, Dr. Chandra Tiwary reported the shocking news that four Black girls, one just 14-months-old, had developed breasts or pubic hair after using hormone-containing hair products. The girls’ pubertal symptoms went away when they stopped using the hair products. A small 2002 study found that, in comparison with white families and immigrant African families, Black-American parents used hormone-containing hair products about four times more frequently on themselves and their children. When I googled "placenta hair care," I found 95 products for sale. The placenta, mostly coming from sheep, is a hormone factory, producing progestins, estrogens and growth hormones in abundance.

Even if a family never uses personal care products with animal placenta or hormones in them, regular hair care products are loaded with all sorts of chemicals that may pose health risks. "Africa’s Best Kids Organics, No-Lye Organic Conditioning Relaxer System with ScalpGuard" sounds safe, doesn’t it? The Environmental Working Group has a very informative website called Skin Deep Cosmetic Safety Database ( where it rates the safety of thousands of personal care products for health effects. One of the categories is a chemical’s potential for disrupting hormones. Out of 78 hair relaxers rated by the group, Africa’s Best is the most dangerous. For those of us who love scents, it is bad news that Skin Deep red-flags all fragrances. "Fragrance" is a catch-all word for 4,000 different chemicals, and one particular fragrance in a product can contain up to 40 chemicals. Big companies reformulate their products as often as every three months, according to an Environmental Working Group research analyst, making it hard for consumers to keep up with which products are safe.

Of the approximately 100,000 synthetic chemicals permeating our environment, 10,000 of them are used in personal care products, and only about 10 percent of those have been tested for safety. The federal government typically relies on chemical manufacturers to do their own testing. Each chemical is tested alone, although humans are exposed every day to hundreds of chemicals that have interacting effects. The U.S. government does not examine whether chemicals we are exposed to affect our hormones, so we can’t look to the government to find out if everyday products are causing girls to reach puberty early.

Other countries have been far more proactive in protecting their citizens. The European Union, for example, banned phthalates in cosmetics in 2003 and in children’s products in 2005. State and local governments do better than the U.S. government. California has banned phthalates in toys and baby products starting in 2009, and other states are taking steps to follow its lead. San Francisco passed a law banning BPA in toys and kids’ products, something that even Europe has not done. Even individual companies are making changes–Deep Rock Water Company in Denver is halting the use of polycarbonate water jugs because they leach BPA.  
My own daughter, who is now almost 10, remains delightfully flat-chested. I pack her school lunches in metal thermoses and metal water bottles. But I cringe as I watch her classmates line up for school lunches heated in plastic, and eat and drink food carried from home in plastic containers. Some of the girls have already grown prominent breasts and with all that I have learned, I am worried about their futures. 
Susan H. Shane is a biologist and mother.