Editor’s note: The following is an excerpt from “The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know,” written by Sandra Steingraber, Ph.D., and published by the Breast Cancer Fund. In the full report (downloadable here), Steingraber reviews several causes of and contributors to early puberty, including environmental factors.
Over the course of just a few decades, the childhoods of U.S. girls have been significantly shortened. Girls get their first periods, on average, a few months earlier than did girls 40 years ago. But they get their breasts, on average, one to two years earlier. Recent studies show that the advent of breast budding — one of the earliest visible signs of puberty — appears to be arriving earlier and earlier in the lives of U.S. girls. We need to know why.
As a biologist, I’m accustomed to distinguishing cause from consequence and consequence from co-variable. But in the puberty story, so many variables are interwoven and interdependent that, as I began to trace the thr... Read more