Former U.S. President Bill Clinton, Microsoft founder Bill Gates and actor Richard Gere all headlined the 16th International AIDS Conference in Toronto Monday, where they called on the world to unite and make the fight against HIV/AIDS a priority.

"It's a breathtaking human tragedy...it's unacceptable," Clinton told a panel discussion that was touted as a "double-Bill."

He said the road ahead would be "rocky" until a vaccine was developed, adding that the biggest problem was that 90 per cent of people who are HIV positive in developing countries don't know it.

"I want to stop people from dying and to give these countries a chance to have a future," said Clinton.

He also said while prevention methods and medicines have helped steady the disease in developing countries, the stigma of having HIV/AIDS was a major stumbling block.

"Having a treatment program that's broadly accessible does start to change the dialogue because then you have healthy people out in the community ideally talking about their status and saying `If you get tested, you can get the drugs'."

Clinton noted the Caribbean was the only region where infection rates were dropping, mainly because it's small enough to manage, he said.

Stigma of HIV/AIDS

Meanwhile, Microsoft Founder and philanthropist Bill Gates said that while rich countries have started to turn a corner in fighting the epidemic, stigma is still a major roadblock in poorer countries.

"We really can't achieve the goals of giving these countries a chance unless we address this epidemic," Gates, who recently donated $500 million US to the fight against HIV/AIDS, told the panel.

The opening of the session was disrupted briefly as chanting protesters held up signs reading: "Fight AIDS, Fund Health Care Workers Now."

Clinton placated the activists when he said: "I agree with that -- we do need a lot more nurses."

At a later panel discussion Monday, Melinda Gates said the power to prevent HIV needed to be put in the hands of women.

One way to do this would be to give women access to a microbicide gel which they could administer to protect themselves from transmission of the virus, Gates told the conference.

"We need to have more trial sites created. We need more communities involved. We need more people willing to come forward to participate in trials,'' she said.

Gates also stressed the importance of addressing the issue of stigma, adding that HIV is transmitted by activities that many societies find hard to discuss.

Musa Njoko, a jazz artist and HIV activist, was one of the first women to disclose her HIV-positive status in her native South Africa.

"We need no longer continue having our lives controlled by other people,'' she told the panel. "It's our time, it's our lives, let's fight for our survival, let us fight for the future of our children.''

Gere's Heroes Project

Actor Richard Gere also spoke Monday calling the threat of AIDS "the true terrorist on the planet today."

Gere is co-chair of the Heroes Project, a three-year initiative to reduce the stigma of AIDS in India.

"In India the incident rate is hovering at around one per cent," said Gere. "If we can keep that level, there's a good possibility that we're not going to see 10 million or 20 million more Indians die, so that's the reason why we do this work."

The project uses mass media and advocacy as its primary tools in the fight against stigmatization and discrimination. Speaking on his role as an advocate, Gere said it was a personal choice.

"I'm not a 26-year-old boy anymore and I look at my life and I have to make some hard decisions of what I can be effective at and be meaningful at with the remaining years that I do have. I distilled that down to several subjects and probably the most important to me was HIV/AIDS."

Empowerment of women

Monday's panel discussions came just hours after hundreds of people took part in a rally to demand urgent action for women and girls in the HIV/AIDS pandemic.

The rally, which featured speakers such as Stephen Lewis, UN Special Envoy for HIV/AIDS in Africa and Louise Binder, of Blueprint for Action on Women and Girls, was followed by a march to the Metro Toronto Convention Centre -- the site of the conference.

"Violence against women and girls, poverty, lack of education and housing, and lack of property rights, all fuel HIV/AIDS infection rates among women and girls," said Binder.

Worldwide, almost 50 per cent of all HIV positive adults are women over 15 years old. In Canada, women represented 27 per cent of positive HIV tests in 2005.

The international conference kicked off Sunday with an appeal by Bill and Melinda Gates to give women and other high-risk groups the ability to protect themselves.

"No matter who she is or what she does, a woman should never need her partner's permission to save her own life," Gates said in his opening speech Sunday.

Sunday's opening speeches were followed by a concert featuring Alicia Keys, Barenaked Ladies, the Blue Man Group, Our Lady Peace, Amanda Marshall and Chantal Kreviazuk.

Conference workshops and plenary sessions officially began Monday.

The sessions are set to deal with a wide range of issues -- from scientific research to caring for those with HIV/AIDS to preventing the spread of the virus, which has killed 25 million people in the last 25 years and infected about 40 million worldwide.