Marcia Herman-Giddens first realized something was changing in young girls in the late 1980s, while she was serving as director for the child abuse team at Duke University Medical Center in Durham, North Carolina. During evaluations of girls who had been abused, Herman-Giddens noticed that many of them had started developing breasts as young as 6 or 7.
“That did not seem right,” said Herman-Giddens, who is now an adjunct professor at the University of North Carolina Gillings School of Global Public Health. She wondered whether girls with early breast development were more likely to be sexually abused, but she could not find any data keeping track of puberty onset in girls in the United States. So she decided to collect it herself.