DESCRIPTION: (Applicant's Abstract) Young men who have sex with men (YMSM) are at high-risk for HIV and other STDs. Major risk behaviors are unprotected multiple partner sexual activity and heavy drug involvement. These risks are of particular concern due to YMSM's lack of contact with prevention services, generally poor health status, manifest psychological distress, and lack of access to medical care for HIV and other STDs. Research on YMSM subpopulations in New York and elsewhere has established the participation of large numbers of YMSM in commercial sex work with men, whether they self-identify as gay or not. This "survival sex" with correlate heavy drug involvement makes them an epidemiological bridge population, with sexual risks from commercial and non-commercial sex, accompanied by risks from drug use, including injection. Research on HIV risk and commercial sex work has been conducted mostly among women, while the research on sexual risk among men who have sex with men focuses on non-commercial sexual relationships among adult (usually gay-identified) men, and most MSM-drug-user research on adults has not been able to disentangle sexual and drug risk behaviors for methodological reasons. An understanding of the social, environmental, psychological, and economic factors that position YMSM in potentially risk-laden sexual transactions is essential to both an epidemiological understanding of this population and formulation of actionable prevention and services recommendations for them. This study will use multiple methods to describe the population of Manhattan young men (age 17-25) who have sex with men; develop a venue-based typology of physical settings, social groups, and sex/drug transactions in which YMSM participate; document patterns associated with initiation into sex/drug risk-taking, including violence and victimization in the life experience of YMSM; compare subpopulations of YMSM on risk and protective practices, including partner selection and sexual transactions; and describe factors including knowledge and attitudes, which facilitate or impede YMSM access to health and prevention services. An initial Community Assessment Process will identify recruitment sites, and provide a background in the environments of YMSM. A year-long ethnographic study will then use four open-ended interviews to identify causes and antecedents to sex and drug risk involvement (emphasizing childhood violence and abuse), profile the everyday means of making a living and the risks they imply, the social and risk networks of YMSM, and their knowledge and use of services (including the role of stigma). A survey instrument, informed by existing literature and findings from the ethnography, will be given to a sample (n=400) recruited by venue-based purposive sampling, to document the prevalence and correlates of antecedents, situations, and risk behaviors previously identified, and carry out the first assessment of depression in this population. A substudy will establish key ethical challenges arising in "participatory" ethnographic research with this population.