Developmental and educational researchers have overlooked the development of sexual orientation among adolescents and youth, even as they study sexual development and identity development during adolescence. This paper examines some conceptual, practical, and ethical considerations involved in conducting research on lesbian, gay, and bisexual youth. It addresses the limitations of current research and the core challenges of conducting such research. The design of a longitudinal study focused on the development of lesbian, gay, and bisexual youth and the impact of stigmatization on their mental health is described to suggest approaches to the challenges inherent in this research.