Guest blogger Kate Tuttle: A study released this week warns about early puberty among American girls. As many as 15 percent of the 7-year-olds studied were already beginning to develop breasts and body hair -- the first signs of the body's transformation from child to sexually mature adult. Even though age at first menstruation hasn't changed much over the past decade, the alarming findings about these early signs has experts and parents concerned.
One reason the study made such explosive news, of course, is that it's not a total shock -- after reading the story, people's comments tended to center on how frequently we've all noticed the phenomenon in our own towns. Similarly unsurprising is the link between early puberty and obesity; we all know that kids are getting heavier (oftentimes ballooning past pleasingly plump into truly dangerous territory) and that along with that weight comes a predictable hormonal shift.
Still, not all obese girls go through puberty early, and not all girls going through early puberty are obese. In fact, among the most mysterious and troubling of the study's findings is that there is a persistent racial gap when it comes to early puberty. While white girls who face early puberty tend to be overweight, black girls are more at risk
no matter what their size. (A full 23 percent of the black 7-year-olds studied were exhibiting signs of early puberty, compared with 15 percent in a similar 1997 study.)
This disparity makes it even more troubling to contemplate the causes of the early-puberty epidemic, which most researchers assume has roots both genetic and environmental
. As with so many public-health concerns, race, economics and region play a big, often hidden, role. Could one factor be the estrogens in baby formulas, whether soy- or cows' milk-based? Could hormones in factory-farmed food be to blame? What about the plastics
that we are increasingly learning play a role in our children's development?
Whatever the causes, the effects could not be less mysterious: When girls mature sexually at an age when their minds are still in early grade school
, they are at risk for teasing, bullying and being sexualized by the adults in their lives. Even if the worst thing that ever happens to a girl is being mocked for having boobs two years before any other girl has them, we all know -- either from personal experience or a friend's -- what a cost that exacts on self-esteem. You only have to see the hunched posture of a young girl hiding her growing chest as she walks down the street. When that girl is already growing up in a world where she'll have to battle racism and sexism, early puberty seems an unfair extra burden.