Monday, August 9, 2010

Puberty: How Early is "Too Early?"

A study published today in the journal Pediatrics indicates that among girls in the United States, the onset of puberty is earlier than it has ever been.

Lead investigator Dr. Frank Biro of Cincinnati Children's Hospital examined approximately 1,200 girls aged 7 and 8 years and determined that among 7-year olds, 10 percent of Caucasian girls and 23 percent of African-American girls had started developing breasts, the earliest sign of pubertal development in girls. Among the 8-year olds, 18 percent of Caucasian girls and 43 percent of African-American girls had entered puberty.

This is a stark contrast from a similar study in 1997, when among 7-year olds, 5 percent of Caucasian and 15 percent of African-American girls had started puberty. In the 1997 study, among 8-year olds, 11 percent of Caucasian girls and 43 percent of African-American girls had started puberty.

But why?