Project Summary Sexual and gender minority (SGM) populations, including adolescents, are at disproportionate risk of HIV/AIDS infection compared to their straight, cisgender peers. SGM youth, however, are not a homogenous population; each has multiple social identities that affect how they are viewed in the world and the risk and protection they experience. Intersectionality refers to ways in which power and privilege are structured based on interrelated social positions (e.g. due to race/ethnicity, immigrant status, native language) and how individual experiences reflect processes that confer privilege and disadvantage. Mutually constitutive forms of social oppression (e.g., stigma simultaneously based on race/ethnicity, gender, and sexual orientation) may differentially affect the HIV prevention and treatment of SGM people with multiple marginalized social positions. Living within these intersecting social positions may give rise to unique challenges as well as strengths that promote healthy development. The 2021 National Academies of Sciences, Engineering, and Medicine consensus study report highlights the need for sexual health research focused on STIs and HIV using an intersectionality framework to inform prevention and intervention efforts, including for youth with marginalized social positions. Building on literature revealing HIV disparities adversely and disproportionately affecting youth, SGM and racially/ethnically diverse communities, the proposed supplement will expand our existing R01 to address the following HIV/AIDS- specific research questions regarding SGM adolescents (13-19 years old): 1) What are differences in HIV testing, HIV status, PrEP experience and attitudes, and high-risk sexual behaviors among youth with different social positions (i.e. racial/ethnic groups, immigrant experiences, and native language)? 2) How do differences in protective factors and other characteristics explain differences in these outcomes among youth with different social positions? and 3) What positive and negative experiences are particularly relevant to the overlapping, simultaneous production of inequalities by SGM identity, race/ethnicity, immigration experiences, and native language? We will answer these questions through two study aims: First, conduct analysis of the 2022 wave of the LGBTQ National Teen Survey (expected N~17,000) to investigate disparities in HIV/AIDS-preventive behaviors, risk, and protective factors among adolescents with intersecting social positions. We will test multiple hypotheses using novel methods designed for studies grounded in an intersectional framework. Second, conduct qualitative interviews with 24-32 SGM youth from different social positions to more deeply understand quantitative findings and generate concrete, valid intervention recommendations. Interviews will focus on exploring how experiences of stigma affect HIV preventive behaviors and what supports youth describe as protective against HIV/AIDS risk. ...