There is evidence that risks for HIV and sexually transmitted infections among adolescent females are higher for those with older male sexual partners. Yet, little empirical research has been conducted with male adolescents who engage in sexual activity with older men. In this article, we summarize in a number of ways the range of sexual activity reported by an ethnically diverse sample of 200 gay and bisexual male youth (15-22 years old) in Chicago and Miami. A general pattern of progression from oral sex with men to both receptive and insertive anal sex with men appeared to characterize the sample during their adolescence. Further, there appeared to be a high degree of "versatile" positioning among the sexually active gay and bisexual young men, in both age-discrepant and age-concordant dyads. Risk analysis revealed having primarily age-concordant partners to be a significant predictor of sexual risk behavior. HIV risk among young gay and bisexual men engaging in sexual activity with older men may occur not only within a distinct biological context from their heterosexual counterparts, but also in a social context that may not as rigidly bound to traditional assumptions about age, gender, and power. The significant associations among participants with partners who were the same age and the risk behavior measures in this analysis have implications for HIV prevention efforts.