Men who have sex with men (MSM) is a research area within the field of public health and sexual health that focuses on the sexual behaviors and health outcomes of men who engage in sexual activity with other men. This research area seeks to understand the prevalence of MSM, the risk factors for HIV and other sexually transmitted infections, and the barriers to accessing healthcare services for this population. Studies in this area often examine issues such as stigma, discrimination, and social determinants of health that may impact the sexual health and well-being of MSM. Public health interventions and policies are also developed based on research findings in this area to improve the sexual health outcomes of MSM.