American girls are entering puberty sooner than was generally thought, lending weight to the argument that sex education should begin early in elementary school, a study in last week’s edition of the journal Pediatrics reports.
Nearly half of the nation’s black girls and 14 percent of its white girls start to develop breasts, pubic hair, or both by age 8, according to a team of researchers at the University of North Carolina at Chapel Hill. They monitored 17,000 girls, ages 3 to 12, who visited their doctors from July 1992 to September 1993.
The study found that the average age for white girls’ breast development was 9.9, a year younger than studies in the 1950s showed. The average age for black girls’ breast growth was 8.8 years. Studies from the 1950s did not provide breakdowns on African-Americans.
Menstruation began at 12.16 years for black girls and at 12.88 years for white girls, on average, the report in the April 7 issue says. While the average age for the onset of menstruation for white girls has remained steady for nearly 50 years, African-American girls are beginning their periods four months earlier than they did in the 1960s.
“There’s not as much of a change in the end of puberty but in the beginning of puberty,” said Marcia E. Herman-Giddens, an associate professor at the school of public health at UNC and the study’s lead researcher.
Although biological differences may play a role in the varying maturation rates of the races, environmental factors also may be a factor, Ms. Herman-Giddens said. Poverty and poor nutrition, which have disproportionately affected more black Americans, may have helped postpone the onset of puberty in the past, she said. Black children may now be better nourished, which could account for the earlier development, she said.
The research also suggests that heightened exposure to environmental estrogens, chemicals that mimic the female hormone, may have helped bring on puberty at an earlier age.
Earlier Sex Ed.?
Many sex education advocates said that the findings from the new study support educating students about sexuality at a younger age.
“When you think about the anxiety these physical changes could cause some young girl, it does them a disservice to not provide them with the information,” said Ruth Mayer, a spokeswoman for the Sexuality and Education Information Council of the United States based in New York City.
Although sex education has been a perennial source of controversy for schools, the vast majority of districts provide general information on puberty beginning in the 5th grade, Ms. Mayer said. “This is compelling evidence that we need to address these issues before 5th grade.”
