Assesses the state of science on the health status of LGBT populations, identifies research gaps and opportunities, and outlines a research agenda for the National Institute of Health. Examines the health status of these populations in three life stages: childhood and adolescence, early/middle adulthood, and later adulthood. At each life stage, the committee studied mental health, physical health, risks and protective factors, health services, and contextual influences. Finds that researchers need more data about the demographics of these populations, improved methods for collecting and analyzing data, and an increased participation of sexual and gender minorities in research. Sets an agenda for “essential” research needed to form a fuller understanding of LGBT health issues.