Sexual and gender minorities (SGM) bear very different burdens of HIV and STI than the general population. Recent reports from the Census Bureau suggest that the proportion of Americans identifying as some form of SGM is growing. However, what is not clear is how these identities impact our understanding of short and long-term sexual behavior trends and changes. An improved understanding of the population is crucial for anticipating changes in prevention needs and, likely, HIV/STI epidemiology. This project aims to compare measures of SGM status for different groups (e.g., gay male, bisexual male, lesbian, bisexual female, trans male, trans female, etc.) across data sources and years, including those with parallel measures of sexual partner genders, to identify the consistency, scale, stability of changing identities, and their relationships to sexual partnering patterns. Future project efforts will utilize these initial findings to model demographic and behavioral shifts and associated changes with one or more STI.