Men who have sex with men with regard to trans women, people born either biologically male or with ambiguous genitalia who self-identify as female. Some sources consider trans women who have sex with men to be MSM, others consider women who are trans "alongside" MSM, and others are internally inconsistent (defining transgender women to be MSM in one place but referring to "MSM and transgender" in another). Determining the number of men who have ever had sex with another man is difficult. Worldwide, at least 3% of men, and perhaps as high as 16% of men, have had sex at least once with a man. These
Men who have sex with men blood donor controversy Men who have sex with men blood donor controversy The men who have sex with men blood donor controversy is the dispute over prohibitions on donations of blood or tissue for organ transplants from men who have sex with men (MSM), a classification of men who engage (or have engaged in the past) in sex with other men, regardless of whether they identify themselves as bisexual, gay, or otherwise. Restrictions on donors are sometimes called "deferrals", since blood donors who are found ineligible may be found eligible at a later date. However, many deferrals are indefinite meaning that donation may