Boys also show signs of early puberty
Boys in the USA start physical changes six months to two years earlier than 30 years ago, research finds.
Boys in the USA are starting puberty six months to two years earlier than 30 to 40 years ago, new research finds — but experts say emotional maturity can’t keep pace with physical changes.
Signs of puberty are now appearing in white boys ( genital and pubic hair growth and early testicular development) at 10.14 years old, more than a year earlier than in a classic British study of white boys in 1969. Black boys show signs of puberty even earlier, at 9.14 years; Hispanics at 10.40.
The findings, based on data from 4,100 boys ages 6 to 16 from 144 pediatric offices in 41 states, follow widely accepted research documenting earlier puberty in U.S. girls. They are in line with findings on early puberty in other countries, says the study in November’s Pediatrics. It was released at the American Academy of Pediatrics’ annual meeting in New Orleans.
The research did not look at what caused earlier puberty, but authors say that “current environmental factors, including exposure to chemicals, changes in diet, less physical activity and other modern lifestyle changes and exposures, may be related.”
Whatever the cause, the outcome has consequences, says Marcia Herman- Giddens, adjunct professor at the University of North Carolina School of Public Health in Chapel Hill and lead author of both the new study and a landmark 1997 study on girls.
“They’re going to be interested earlier in sexual activity and other behaviors associated with adolescence that may be high-risk behaviors,” she says.
Jane Mendle, director of the Adolescent Transitions Lab at Cornell University in Ithaca, N.Y., notes that “just because a child looks mature doesn’t mean he is necessarily ready for the social and emotional challenges” that come with maturity.
Pediatrician Frank Biro, director of adolescent medicine at Cincinnati Children’s Hospital Medical Center, says it would be “a gross oversimplification” to assume differences in onset of puberty are related only to genetic differences among racial and ethnic groups.
“Race and ethnicity incorporate a lot of different factors, some genetic, some cultural,” says Biro, who studies early maturation in girls and was not involved in the new study.