Men who have sex with men are a key population in the global response to HIV. Global targets are for 95% of men who have sex with men to be reached by HIV prevention, diagnosis and treatment services by 2025. To monitor progress to these important targets, estimates of the number of men who have sex with men need to be as close to the true number as possible. Many countries currently underestimate the number of men who have sex with men due to structural issues that make recommended population size estimate methods difficult to carry out. However, data from those countries with valid and sound estimates reported through the Global AIDS Monitoring system show that at least 1% of all adult men have had sex with another man in the last one year, regardless of which region of the world the estimates come from. WHO and UNAIDS recommend that countries adjust size estimates of men who have sex with men to ensure that the estimated number of adult men who have sex with men is at least 1% of all adult men and to use revised estimates for planning and monitoring services.
