Men who have sex with men (MSM) are male persons who engage in sexual activity with members of the same sex. The term was created in the 1990s by epidemiologists to study the spread of disease among all men who have sex with men, regardless of sexual identity, to include, for example, male prostitutes. The term is often used in medical literature and social research to describe such men as a group for research studies. It does not describe any specific sexual activity, and which activities are covered by the term depends on context. The term men who have sex with men had been in use in public health discussions, especially in the context of HIV/AIDS, since 1990 or earlier, but the coining of the initialism by Glick et al. in 1994 "signaled the crystallization of a new concept." This behavioral concept comes from two distinct academic perspectives. First, it was pursued by epidemiologists seeking behavioral categories that would offer better analytical concepts for the study of disease-risk than identity-based categories (such as "gay", "bisexual", or "straight"), because a man who self-identifies as gay or bisexual is not necessarily sexually active with men, and someone who identifies as straight might be sexually active with men. Second, its usage is tied to criticism of sexual identity terms prevalent in social construction literature which typically rejected the use of identity-based concepts across cultural and historical contexts. The Huffington Post postulates that the term MSM was created by Cleo Manago, the man who is also credited for coining the term same gender loving (SGL). MSM are not limited to small, self-identified, and visible sub-populations. MSM and gay refer to different things: behaviors and social identities. MSM refers to sexual activities between men, regardless of how they identify, whereas gay can include those activities but is more broadly seen as a cultural identity. Homosexuality refers to sexual/romantic attraction between members of the same sex and may or may not include romantic relationships.