Over the past decade, Cambodia has lowered its national HIV infection rate from 3.7 percent to 0.9 percent. Yet among Cambodian men who have sex with other men (MSM), the rate is 8.7 percent: nearly 10 times that of the general population.

The reasons are many. Homosexuality isn’t illegal in Cambodia—as it is in nearby countries such as Myanmar and Malaysia—but it is highly stigmatized.The country’s HIV programs, meanwhile, target heterosexuals and sex workers. And whether in Cambodia or Colorado, MSM often have female sex partners and don’t identify as “gay.” They elude the few same-sex campaigns—free HIV testing, condoms, education—that do exist.

Steve Taravella of Family Health International, a global nonprofit group working to stem HIV infections among Cambodian MSM, says, “When men are unable to acknowledge having sexual relations with other men, even to their health care provider, it makes them harder to reach.”