While the biological signs of female puberty — menstruation, breast development, and growth of pubic and underarm hair — typically occurred around 13 years of age or older just decades ago, today girls as young as 8 are increasingly showing these signs.
African-American girls are particularly vulnerable to early puberty.
According to biologist Sandra Steingraber, the author of the report titled “The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know,” “The data indicates that if you get your first period before age 12, your risk of breast cancer is 50 percent higher than if you get it at age 16.”
“For every year we could delay a girl‘s first menstrual period,” she says, “we could prevent thousands of breast cancers.”
Theories behind what is causing the early-puberty trend abound, but the actual causes are not known. Potential causes noted in the paper include:
- Rising childhood obesity rates and inactivity
- Formula-feeding of infants
- Excessive TV viewing and media use
- Family stress
- Exposure to environmental chemicals
Early puberty is likely an “ecological disorder,” according to Steingraber, that’s being caused by a number of environmental factors.
Chicago Tribune September 16, 2007