CHICAGO – When it comes to the birds and the bees, some parents may want to have that talk with their boys a little sooner than they expected.
Researchers have found signs of puberty in American boys up to two years earlier than previously reported – age 9 on average for blacks, 10 for whites and Hispanics. Other studies have suggested that girls, too, are entering puberty younger.
Why is this happening? Theories include higher levels of obesity, inactivity, and chemicals in food and water, all of which might interfere with normal hormone production. But those are just theories, and they remain unproven.
Doctors say earlier puberty is not necessarily cause for concern. And some experts question whether the trend is even real.
Dr. William Adelman, an adolescent medicine specialist in the Baltimore area, says the new research is the first to find early, strong physical evidence that boys are maturing earlier. But he added that the study still isnt proof and said it raises a lot of questions.
Earlier research based on 20-year-old national data also suggested a trend toward early puberty in boys, but it was based on less rigorous information. The new study involved testes measurements in more than 4,000 boys. Enlargement of testes is generally the earliest sign of puberty in boys.
The study was published online today in Pediatrics to coincide with the American Academy of Pediatrics national conference in New Orleans.
Dr. Neerav Desai, an adolescent medicine specialist at Vanderbilt University in Nashville, said hes seen a subtle trend toward slightly earlier puberty in boys. He said its important for parents and doctors to be aware so they can help children emotionally prepare for the changes that come with puberty.
Problems such as thyroid abnormalities and brain tumors have been linked to early puberty. But boys with chronic medical conditions or who were using medicines that could affect puberty were excluded from the research.
If its true that boys are starting puberty younger, its not clear that means anything negative or has any implications for long-term, said Adelman, a member of the American Academy of Pediatrics committee on adolescence.
For the new study, researchers recruited pediatricians in 41 states who participate in the academys office-based research network. Doctors asked parents and boys aged 6 to 16 to take part during regular checkups. The visits took place between 2005 and 2010.
Half of the boys were white. The rest were almost evenly divided among blacks and Hispanics.
Dr. Dianne Deplewski, a pediatric endocrinologist at the University of Chicago, has not seen any increase in boys referred to her for signs of early puberty. She said its possible that the new study results were skewed by families who brought their boys to the doctor because they already had concerns about their health.
She said the research methods werent perfect but that theyre the best to date. She also stressed that the results shouldnt be used to establish a new normal for the start of puberty in boys.
Just because this is happening doesnt mean this is normal or healthy, the researcher said.