CONTEXT: Little is known about the prevalence and correlates of same-sex sexual activity among teenagers and young adults, particularly those who do not identify themselves as gay, lesbian or bisexual. Effective interventions to prevent STDs require accurate understanding of youths’ sexual behavior.

METHODs: Descriptive and regression analyses of data from the 2002 National Survey of Family Growth examined patterns and correlates of same-sex sexual activity among a sample of 2,688 never-married, noncohabiting men and women aged 15–21. Same-sex behavior was assessed separately by gender, as well as by heterosexual experience and sexual attraction and identity.

RESULTS: Eleven percent of women and 4% of men reported same-sex sexual experience. Youth who were attracted only to the opposite sex had a decreased likelihood of reporting same-sex activity (rate ratio, 0.1 for each gender), while women and men who identified themselves as homosexual or bisexual had an elevated likelihood of such activity (5.1 and 5.9, respectively). However, among women who were attracted exclusively to men, those who had had heterosexual sex were more than four times as likely as those who had not to have engaged in same-sex activity. Finally, among youth who reported any same-sex attraction, women and men who said they were homosexual or bisexual had an elevated likelihood of having engaged in same-sex behavior (4.7 and 5.6, respectively).

CONCLUSION: A significant proportion of “straight” youth engage in same-sex activity, and so information on risks associated with such behavior should be included in sex education programs and targeted to all youth.