Kofi Annan has warned that winning the battle against Aids means acknowledging that homosexuals, prostitutes and injecting drug users are at particular risk and need protection.
The secretary general of the United Nations told delegates from around the world at a global conference on the disease in New York that while the rate of spread of the disease may be slowing, funding needs to be tripled by 2008 to about $22bn (£11.7bn) worldwide.
He said that there needs to be improved prevention and also better medical care for those already infected with HIV, the virus that causes Aids. Forty million people have the virus.
The conference is taking place held nearly a month before the 25th anniversary of the first Aids case being diagnosed, on 25 June 1981.
But progress towards a final agreement is being hampered by a reluctance of some African, Islamic and conservative Latin American countries to include any specific reference to gays and other fringe groups.
"We need to be realistic," Mr Annan said. "If we are here to try to end the epidemic and fight the epidemic, we will not succeed by putting our heads in the sand and pretending these people do not exist or do not need help." He went on: "We must work closely and constructively with those who have so often been marginalised; sex workers, injecting drug users and men who have sex with men."
The United States displayed some of the same squeamishness regarding homosexuals at the last such UN conference in 2001 but it made clear this week that it has relaxed its attitude. Kirsten Silverberg, an Assistant Secretary of State, said: "We would love the mention of vulnerable populations, generally, specifically."
But the US is balking at a European Union proposal to detail prevention programmes for gays, sex workers and needle-users.
The secretary general, attempting to introduce a greater sense of urgency to the meeting, said the virus "has spread further, faster and with more catastrophic long-term effects than any other disease.
"Its impact has become a devastating obstacle to the progress of humankind."
The UN report introduced at the start of the conference said drug treatment is available to only fewer than half of those already infected with HIV.
Dr Peter Piot, the head of the UNAIDS programme, said: "We need to commit to a strategic approach that recognises Aids both as a long-term priority as well as an emergency that requires an immediate response. In other words, we need to run a marathon at the pace of a sprint."
Of the $22bn Dr Piot says will be needed from donor governments in 2008, half will be earmarked for prevention and a quarter for the treatment and care of those infected.
The remainder will be used to care for orphans and other children at risk, as well as the costs of running the UNAIDS programme.
Third World attitudes to homosexuality
AFRICA: Laws against male homosexuality exist in most African nations, where it is generally frowned upon across all spectrums of society. The existence of gay women, on the other hand, is rarely recognised. In Uganda, where gay relationships can be punished by life in prison, President Yoweri Museveni has frequently ordered round-ups of anyone suspected of being gay. Zimbabwe's President Robert Mugabe has called homosexuals "worse than dogs and pigs". Last month newspapers in Cameroon allegedly outed a number of prominent politicians.
LATIN AMERICA: While Brazil has a long tradition of accepting homosexuality, and few Latin American countries have laws prohibiting it, gay men and women routinely suffer persecution in more conservative Catholic nations such as Chile, Bolivia, Colombia and Mexico.
ISLAMIC NATIONS: Most predominantly Muslim nations have laws outlawing same-sex relationships. The level of repression varies from nation to nation. Persecution is greater in countries where most citizens adhere to a strict interpretation of Islam, such as Wahabism and Deobandism, or where the legal system is based on a strict interpretation of sharia law. The Gulf states, plus Morocco, Algeria, Tunisia, Iran and Malaysia, all outlaw homosexuality.