Slightly more than half (55%) of 15–19-year-olds have engaged in heterosexual oral sex, 50% have engaged in vaginal sex and 11% have had anal sex, according to a new Guttmacher Institute study. However, both oral and anal sex are much more common among teens who have already had vaginal intercourse than among those who have not, suggesting that teens initiate a range of sexual activities around the same time, rather than substitute one for another.

"There is a widespread belief that teens engage in nonvaginal forms of sex, especially oral sex, as a way to be sexually active while still claiming that technically, they are virgins," says study author Laura Lindberg. "However, our research shows that this supposed substitution of oral sex for vaginal sex is largely a myth. There is no good evidence that teens who have not had intercourse engage in oral sex with a series of partners."

Some teens may first experience oral sex immediately prior to vaginal intercourse, while others may initiate vaginal intercourse shortly before having oral sex. While only one in four teen virgins (26%) have engaged in oral sex, once teens have had vaginal intercourse, the proportion increases incrementally. By six months after first vaginal sex, more than four out of five adolescents (81%) have also engaged in oral sex, and by three years after first intercourse, nine in 10 (92%) have done so.

"The study has clear policy implications," says Lindberg, a senior research associate at the Guttmacher Institute. "While oral and anal sex carry no risk of pregnancy, engaging in these behaviors can nevertheless put teens at risk of sexually transmitted infections (STIs). Counseling and education should take into account total STI risk by addressing the full range of behaviors that teens engage in, including oral and anal sex. It is crucial that teens receive evidence-based education and counseling about STI risks and protective behaviors for all types of sexual activity. The federal government’s exclusive emphasis on abstinence-only-until-marriage programs does not give teens the skills and information they need to be safe."

"Non-Coital Sexual Activities Among Adolescents," by Laura Lindberg et al., is currently available on the Journal of Adolescent Health’s Web site and is scheduled to be published in the July 2008 issue of the journal. The study analyzes data on 15–19-year-olds from the 2002 National Survey of Family Growth. Although this is the first time the federal government has measured the prevalence of both oral and anal sex and so no direct trend data are available, comparisons of these data with those from other nationally representative surveys (such as the National Survey of Men, the National Health and Social Life Survey, and the National Survey of Adolescent Males) find little change in oral sex among opposite-sex partners in the past decade.