Are Boys Reaching Puberty Earlier?
Controversial researcher says yes
FRIDAY, Sept. 14, 2001 (HealthDayNews) -- The researcher who created a controversy several years ago by reporting that American girls are reaching puberty earlier than ever now says the same thing seems to be happening to American boys.
The evidence is far from conclusive, says the researcher, Marcia Herman-Giddens, a professor of public health at the University of University of North Carolina at Chapel Hill. But her analysis of data from a nationwide study indicates that boys may be experiencing puberty up to six months earlier than previous research indicated.
She bases that belief on data on 2,114 boys who took part in a National Health and Nutrition Examination Survey between 1988 and 1994. That data showed that the first signs of puberty appeared in white boys at 12 years, in African-American boys at 11.2 years and in Mexican-American boys at 12.3 years. Standard reference books generally list the average age of puberty for boys at about 13 years.
Her report appears in today's issue of the Archives of Pediatric and Adolescent Medicine.
Herman-Giddens quickly acknowledges that her finding must be confirmed by other, more detailed studies because hers is based on just two indicators of male puberty -- the appearance of pubic hair and growth of the testes. A definitive finding would have to be based on what she says is the male equivalent of the onset of menstruation: the age of first ejaculation.
"But we are hung up and weird about sexuality here, and somehow it is taboo to ask boys if they have had their first ejaculation," she says. "Other countries aren't as hung up about it."
A Finnish study that asked the question found that 38.9 percent of boys there ejaculated before age 13, she says, "but we don't have that figure here."
The only way to settle the issue is to have a large-scale study by many researchers using the same [Finnish] methodology, Herman-Giddens says. "I am trying to get one underway," she says.
One cause of earlier puberty in boys could be obesity, which is clearly related to puberty in girls, Herman-Giddens says. "But the link is much weaker in boys than in girls," she says. One in five U.S. children is currently classified as obese, according to the American Academy of Family Physicians.
The new finding is called "doubtful" by Dr. Edward O. Reiter, a pediatric endocrinologist at Baystate Medical Center Children's Hospital in Springfield, Mass. One reason is that the presence of pubic hair was determined just by "a quick physical examination." A number of boys ages 8 and 9 were reported to have pubic hair, "which I felt to be probably an overabundant percentage for that age," he says.
Another question concerns the statistics of the study. "The range of acceptable error in the data was very high," Reiter says. "I have problems with studies of this nature."
Like Herman-Giddens, Reiter says the issue can be resolved only by "a careful, detailed study by an organization like the American Academy of Pediatrics."
The earlier finding about the early onset of puberty for girls remains "somewhat controversial," Reiter says. While the Lawson Wilkins Pediatric Endocrine Society, a group of doctors specializing in early puberty, has lowered its estimate for the average age of puberty to 9 years for African-American girls and 10 years for white girls, many endocrinologists do not accept the new numbers. Reiter is president of the society.
In both boys and girls, doctors must be alert for the signs of premature puberty, which can cause physical problems, Reiter says. The flood of hormones may stop bones from growing and has also been linked to breast cancer.
And however controversial Herman-Giddens' findings may be, he says, they are valuable because "they raise interest in the subject, get a lot of people involved and help determine what kind of studies we should do."
What To Do
"If you take a boy to the pediatrician, say he's 7½, and the doctor notices a little enlargement of the testes, a first sign of puberty, the correct thing is to say, 'Maybe that's normal, maybe not,'" Reiter says. "You need to observe the pattern of pubertal change, tell the pediatrician what you see and come back in three months."