Adolescents face many barriers in accessing appropriate primary care. Among the most underserved are lesbian, gay, and bisexual youth who are often neglected by traditional systems of care. This is a reference guide that provides background knowledge, substantive references, and detailed information on the stressors, health needs, experiences, and developmental challenges facing lesbian and gay youth. The first part focuses on experiences and needs of lesbian and gay adolescents-health challenges, identity development, their experiences, vulnerabilities, and risks, and confidentiality and legal issues that are of concern. The second part deals with primary care and disease prevention objectives in this group of adolescents-most frequent health concerns, issues of transgendered youth, special populations, primary interventions and anticipatory guidance, medical assessment, treatment, and prevention, and mental health concerns, assessment, and treatment. The third part presents an overview of HIV infection in all adolescents, with a focus on issues of concern for lesbians and gay males. It covers issues of HIV counseling, testing, and prevention as well as clinical care and prevention. Several appendices offer additional resources for primary care needs of lesbian and gay adolescents, resources for parents and youth, recommended reading for providers, adolescent HIV counseling and testing protocols and clinical care protocols.