“I wanted to call the book The New Normal, but everyone around me said no, you can’t!” said Louise Greenspan, a pediatric endocrinologist and co-author of a book that ended up being called The New Puberty: How to Navigate Early Development in Today’s Girls, on Sunday at Spotlight Health, a conference co-hosted by the Aspen Institute and The Atlantic. “It may be average, but it’s not okay.”
Greenspan is also a co-author of a longitudinal study that looked at around 1,200 girls ages six to eight, and followed them for seven years, from 2004 to 2011, to see when puberty began for them. While puberty in girls is often measured using the onset of their first menstrual period, the first sign is actually breast development—it’s just that first period is easier to measure, because people typically remember it. For breast development, a doctor really has to do an in-person exam. (Puberty onset in boys hasn’t been well-studied, but it doesn’t seem to be following these same patterns.)
The results were staggering. “When I was in training, I was told that age eight was the earliest age that a normal, healthy girl would start breast budding,” Greenspan said. The median age of breast budding in the study varied by race, with the lowest median at 8.8 years for black girls, and the highest at 9.7 for Asian girls. Since these are the median ages, that means half of girls were developing even earlier than that.