August 12, 2010
When the story that girls are reaching puberty earlier than ever began popping up everywhere this week, I did not doubt its veracity. It was no coincidence that I received an email from a friend yesterday, observing with mixed feelings that she had just purchased a first bra for her oldest daughter. Her daughter is 9.
News about girls reaching puberty earlier and earlier isn’t exactly new. We saw a flurry of stories in late 2009, when studies found an association between early menarche, late menopause and breast cancer. Additionally, the finding that African American girls often show signs of pubertal development earlier than other girls is well-established.
The study that triggered this new explosion of publicity, published this week in Pediatrics, assessed girls’ development by evaluating the size of breast buds (as breasts are called in early stages of development). The researchers evaluated an ethnically diverse population of 1,239 girls ages 6 to 8 across three research sites. They found that 10.4 percent of white, 23.4 percent of black and 14.9 percent of Hispanic 7-year-olds had reached “Sexual Maturation Stage 2.” Stage 2 is more typically reached at age 10, but may occur any time from age 8 to age 13. Menarche, the first menstrual period, occurs on average at age 12, in Stage 4, but it, too, varies, occurring as early as age 9 and as late as age 17.