"If you want to achieve zero new infections, you have to address the human rights issues," WHO official Ying-Ru Lo said after a meeting about infection rates among gay men at the International Conference for AIDS and sexually transmitted infections in Africa (ICASA).
She said stigmatisation and high levels of discrimination blocked access to Aids treatment, boosting infection rates among gay men in developing countries.
"We must ensure the well-being of the most marginalised groups," she added.
Men who have sex with men are 19 times more likely to contract HIV/Aids in lower income countries, according to a 2011 WHO report.
Africa is the region hardest hit by epidemic.
Homosexuality is illegal in more than 75 countries of the world, and is widely considered taboo in Africa.
The director general of the African Medical and Research Foundation, Teguest Guerma, said it would take time to create laws protecting gay rights, but speaking openly about homosexuality was a crucial first step.
"In the past they were really underground, at least now they are coming to the surface," she said.
The ICASA conference in the Ethiopian capital has scheduled three sessions concerning the rights of homosexuals affected by HIV/Aids.
(Sapa, December 2011)