"Men with men" is a phrase that is used to describe men who participate in activities of a sexual nature with other men. A common acronym for men who have sex with men is MSM.
Men who have sex with men constitute about 2 percent of the U.S. population, as of 2015, and are disproportionately affected by the Human Immunodeficiency Virus, or HIV, and Acquired Immunodeficiency Syndrome, or AIDS. According to the CDC in 2013, the most recently available data, 65 percent of the 47,352 cases of newly diagnosed HIV cases were for MSM. In response to this, the CDC is allotting an additional $55 million over five years to provide HIV testing to communities, and is also directing marketing efforts for AIDS awareness toward MSM.