A new study found the similar to girls, American boys are likely to enter into puberty earlier than boys of previous generations.
A study, led by author Marcia Herman-Giddens from the University of North Carolina's School of Public Health and her colleagues found that American boys in the current generation are starting to sexually develop six months to two years earlier than boys of previous generations.
Similar studies have been conducted in the past but haven't reached any suitable findings, because, according to Herman-Giddens, the onset of puberty in boys is difficult to determine.
"With girls, the first signs are obvious, and social ramifications are much more pronounced and they're negative," said Dr. William P. Adelman, associate professor of pediatrics at the Uniformed Services University of the Health Sciences in Bethesda, Md., and a member of the Academy of Pedatrics committee on adolescents.
But early-maturing boys "get called on more in school, tend to be better athletes. I'm less likely to get a parent of a boy saying, 'Oh my gosh, my boy's developing - he's too young,'" Dr. Adelman said. More common is, "My boy, he's a freshman in high school, his best friend is 6 feet already and he's 4-11."
For girls, start of the menstrual cycle and development of breasts can be deemed as the onset of puberty but for boys it's the enlargement of testes and development of sperm.
"'Yikes, we don't want to ask about that!' " Herman-Giddens said with a laugh.
However, 12 researchers across the country examined more than 4,100 boys aged 6 to 16. The study involved recording information on the boys' genital size and pubic hair appearance. These records were categorized into four stages. Stage 1 was the pre-puberty stage, Stage 2 - onset of puberty, Stage 4 and 5 were stages of puberty and stage 5 was adult maturity.
The findings were then divided on the bases of race and it was found that African-American boys start hitting puberty first, at about 9 years old, while non-Hispanic white and Hispanic boys begin developing around 10 years old. "This should have an impact on the public health community," Herman-Giddens said.
"That might be normal now," she said, "but that doesn't mean it's normal in the sense of what's healthy or what should be."
"The changes are too fast," Herman-Giddes said. "Genetics take maybe hundreds, thousands of years. You have to look at something in the environment. That would include everything from (a lack of) exercise to junk food to TV to chemicals."
"It was an important study to do, and their methodology is improved over prior studies in that they based their assessment of puberty in boys on what I consider to be the gold standard: the size of the testicles," said Dr. Laura Bachrach, a professor of pediatric endocrinology at Stanford University.
