20121224_me_07.mp3?orgId=1&topicId=1128&d=246&p=3&story=167735056&t=progseg&e=167717021&seg=7&ft=nprml&f=167735056

It's been known for a while that girls start puberty earlier than they did in the past, sometimes as young as 7 or 8. But it's been unclear whether boys also go through puberty earlier. Now, a study from the American Academy of Pediatrics helps answer that question.

Marcia Herman-Giddens is a public health researcher at the University of North Carolina. She did the original studies looking at early puberty in girls. Now, she has replicated those studies with more than 4,000 boys. And the findings are similar: Boys are entering puberty six months to two years earlier than they did in past studies.

There are racial differences. Caucasian boys tend to begin puberty, on average, around 10 years old while African-American boys tend to begin puberty at 9.

As with girls, researchers don't know why, but they have some ideas. Most have to do with the modern environment, starting with easy access to lots of food. "We have often talked about the problem of obesity and overweight, along with the easy availability of fast food, adding up to what some people call 'overnutrition,' or abundance of calories," says Herman-Giddens.

For girls, being overweight has been linked to early puberty. And that could also be the case for boys. Another possible trigger for girls: estrogenlike chemicals in the environment. That hasn't been proved — and it's most likely not a cause for boys, because estrogen isn't involved in the changes that come with puberty.

Whatever the reason, Herman-Giddens says the focus now should be on helping boys cope: "Just because the child's body is developing sexually earlier, that doesn't mean their cognition, judgment and other mental abilities that go along with becoming an adult are becoming earlier. They are not."

And, for parents, early puberty can be a trying time. Fred Goodall, the father of a 9-year-old boy, thought he wouldn't have to have the puberty "talk" for a few more years. Goodall wrote about his daughter going through puberty on his parenting blog, Mocha Dad.

Now, with his son, there are similar feelings; a bit of sadness, a sort of premature loss of innocence. "He still plays with Legos, and action figures; he reads comic books and wants me to give him piggy back rides; things like that; all these things are not things you associate with puberty. He's still a little boy in my eyes."

It's easier to tell when girls are going through puberty because of developing breasts and menstruation. In a way, a boy's developing puberty is nearly invisible, says Vermont pediatrician Richard Wasserman, who heads the research arm of the pediatrics academy.

Wasserman says the best way to deal with early puberty is to have a very specific and detailed discussion with your son about how his body is going to change. "He needs to be helped to understand that his body is changing and will continue to change as he progresses from being a boy to being a young man," says Wasserman.

This is where doctors and even books can help parents guide their child. Goodall just bought a book and hopes to have the talk during the holidays when his son is off school. "I want to give him time to have it sink in," he says.

The important thing, says Wasserman, is for your child to be comfortable in his new and developing body. "An earlier-maturing boy may ... be bigger and stronger," which could be a big plus in sports. But at the same time, "he may also feel awkward, clumsy and he may get teased."

Copyright 2016 NPR. To see more, visit http://www.npr.org/.