Breasts at 7 Years Old: How Chemical Hazards May Wreak Havoc on Children's Bodies

Photo Credit: Art Gingham/Library of Congress

When a little girl starts growing breasts a year after losing her first baby tooth, her parents probably understand the situation as little as she does. And when it happens to girls across the country, and to many girls growing up in certain neighborhoods but not others, scientists struggle to explain the phenomenon as well.

Women's bodies have always carried biological freight from one generation to the next, bearing the physical imprint of industry and environmental loss. One of the most confounding effects of environmental change is precocious puberty among girls -- taking the form of an unusually young first period, early growth of pubic hair, or breast buds in the first grade -- which may be tied to where families live, the products they consume, and how healthy and happy they'll be later in life.

Various studies have suggested that the process of puberty may be influenced by exposure to a particular class of chemicals, known as endocrine disruptors, found in everyday products like water bottles, food packaging and cosmetics.

Chemistry No One Can Avoid

Endocrine disruptors change our body chemistry by altering the function of hormones, which dictate the way our bodies develop and behave. While many questions have arisen about the potential threats these chemicals pose to our health, numerous human and animal studies in recent years suggest significant, but often invidious, effects on growth, reproductive development, and, over time, risk of cancers and other diseases. An endocrine disuptor might "mimic" a pregnant woman’s natural estrogen and change the way the fetus develops, for instance. Or her shampoo could expose her every day to a chemical linked to aggressive or disruptive behavior in young children.

According to a review of environmental research by the Breast Cancer Fund, study after study has identified alarming twists in hormonal and child development -- including disruptions in puberty and elevated cancer risk in some cases -- that are tied to chemicals in cosmetics, building materials, detergents, vehicle exhaust and even baby formula packaging.

Whatever the health effects, no community can escape exposure to endocrine disruptors in a modern habitat, where toxins constantly mesh with the way we eat, work and play. Meanwhile, new research shows that the "body burden" of industrial chemicals also reflects and exacerbates divides of race, class and gender. Not only are endocrine disruptors increasingly pervasive among American women and girls; the consequences of this contamination tie into race and socioeconomic circumstance in ways we're just beginning to understand.

Last year, a group of researchers published findings of a study involving more than 1,200 girls, about six to nine years old, which showed that black and Latina girls displayed signs of puberty at a younger age than white peers, some developing breasts as young as seven years old. In an examination of related data on chemical exposures, the group also found that "Hormonally active environmental agents" had "small associations with pubertal development."

The findings reaffirmed previous studies that point to a nexus of puberty, race and chemicals in children's bodies. While scientists stress such findings are inconclusive, the mounting evidence of the chemical connection could illuminate a hidden dimension to environmental injustice in communities of color.

Big Girls

According to a 2007 report by the Breast Cancer Fund, the age range of puberty has been declining for American girls in general, but the patterns differ by race. The age of the first period for black girls has consistently been slightly younger than that for whites, the report stated, and "over the course of the 20th century, age at menarche fell faster and farther for U.S. black girls than for U.S. white girls." There has been a similar downward shift over the past 40 years for Mexican American girls. Other studies on girls in Europe did not indicate parallel trends.