Research Watch: Boys To Men

Diana Zuckerman
October 1, 2001

The early sexual development of girls has received tremendous media attention, but there has been no similar attention to boys’ development. A new study of signs of puberty among boys 8 and older may change that, because it shows that boys are also maturing earlier than expected.

The data were collected between 1988 and 1996 from 2,114 boys who were part of the National Health and Nutrition Examination Survey III. This survey is conducted by the U.S. Department of Health and Human Services and represents more than 16 million boys living at home, between 8 and 19 years old. The survey is a major undertaking and this analysis of boys is the first national study of its kind. It’s easy to understand why: What parents would bring their child to a doctor for a study in which the child must strip naked so the doctor can evaluate the development of pubic hair and genitals?

The results are similar to the earlier study of girls, in that they indicate that boys are starting puberty earlier than previously believed, and that African-American children are ahead of other racial groups. As early as 8 years old, 38 percent of the African American boys had started genital development, as had approximately 28 percent of white and Mexican-American boys. By age 9, 58 percent of the African-American boys and approximately one-third of the white and Mexican-American boys had started genital development. Pubic hair growth started later, but there were similar racial differences.

Although the African-American boys start to develop earlier, the white and Mexican-American boys catch up by age 13 for this first stage of genital development and by 14 for starting pubic hair. In fact, at 14, approximately 5 percent of African-American boys were not showing the first signs of puberty, a slightly higher percentage than the other boys.

It may seem odd to discuss genital development in Youth Today, but this study has tremendous implications for youth workers. Most adults think that kids are growing up too fast – much faster than today’s adults did – but this study shows that there may be a biological basis for this growth, not just a cultural one.

Unfortunately, it’s difficult to know for certain because the only comparable data is from a 1969 study conducted in England. The study was based on photographs rather than clinical exams, and the findings may have been influenced by the fact that all the boys and girls were white and institutionalized. Nevertheless, it is important to note that, on average, the boys in that study started pubertal development (known as Tanner Stage 2 in medical lingo) at 11.6 years of age – a year-and-a-half later than in this new study. The data for girls show a similar earlier start for breast development and pubic hair, but not for menstruation.

As youth workers try to help preteens and young teens steer clear of risky behaviors, it is helpful to understand that many kids are starting to experience hormonal changes and sexual development in third and fourth grade. They are not fully developed yet – the statistics are based on the first signs of genital development – but as a result of these changes they may feel more “grown-up” than they are.

The study does not examine the boys’ behavior or adjustment, but previous studies of girls have indicated that early puberty is linked to depression, drug and alcohol use and early sexual activity. Young children who look older may tend to hang out with older kids, and may feel a need to prove themselves by acting older. They will need guidance and support from youth workers and other adults, who must be aware that despite the physical changes, these are still young children whose judgment is probably not as mature as is their appearance.

Zuckerman, Diana. "Boys To Men." Research Watch review of “Secondary Sexual Characteristics in Boys.” Youth Today, October 2001, p. 26-27.

©2000 Youth Today. Reprinted with permission from Youth Today. All rights reserved.