As today is World AIDS day, Xu Chi speaks to the man behind a local organization that has spent the past six years supporting the rights and welfare of sex workers in Shanghai - some more unfortunate than others.

They called him "Mary." He was a middle-aged male sex worker, a transvestite, an uncle of two young nephews back in Hebei Province and, most importantly, an AIDS-prevention volunteer.

Mary always had a beautiful little dream that he wanted to leave something to the world at the dawn of his life, even though the only people that mattered in his world were his nephews and his customers; his other relatives weren't included as they were ashamed of him.

The "something" he could give to his nephews was the money he earned from the sex trade, and to his customers, firm insistence on using condoms and his own rapid health checks to prevent catching and spreading the AIDS virus.

However, his well-designed plan was ruined by his sudden death at the age of 50. He died in 2007 of high blood pressure and a series of venereal diseases as a result of his excessive sex work fuelled by his eagerness to achieve his dream.

At his simple funeral, Mary's relatives came to the city for the first time to glance at their "shameful" family member one last time, together with mourners including other AIDS-prevention volunteers from Shanghai Leyi, an NGO aiming to help the city's sex workers.

Mary's two nephews received a bank card with his life savings, several hundreds of thousands of yuan. And the only question they asked after getting the card was "So what's the password?"

Mary's ashes were wrapped in red cloth by the volunteers because his relatives refused to purchase him a cinerary casket; the volunteers took a cab to transfer the package to Mary's hometown because no one would pay for a hearse.

When Tony Zheng, founder and chief director of Shanghai Leyi and quite a comrade to Mary, was telling the story, he was so calm that he spoke with the mildest of sorrow that barely rose above the level of indifference.

He is not indifferent. He has seen too many Marys in his past six years' work for the organization and he knows clearly that emotion alone won't overpower the reality which is presented without any make-up but only its "naked body" - cruelty.

To Zheng, Mary was treated as a sex machine for punters to vent their lust, a prey for police to hunt and a bank account for his relatives to squander, instead of a human being to be loved and an AIDS-prevention volunteer to be respected.

Zheng knows some sex workers who have been raped by their customers when they refuse to offer certain services and some who have been beaten or even stabbed, but they dared not make a sound.

They came to Shanghai Leyi, and that's what exactly Zheng and the organization are struggling for - to protect the rights of sex workers, male, female and transvestite.

As they are not able to stop prostitution, the organization aims to create a better, safer environment for sex workers so they can at least live as a normal human being after work, not just a criminal living a criminal's life: running the illegal business, hiding from police or dying alone.

"Regardless of the rights or wrongs of being prostitutes, they are still people who have their rights," says Zheng. "The idea of their rights has long been ignored by others and the sex workers don't know what rights they have."

Zheng believes the idea is also important to the course of AIDS prevention, as sex workers are among the main transmitters of the virus, but if they knew how to protect themselves and their customers, they could prevent the virus from being spread.

Zheng, 31, came from Fujian Province six years ago to join his young male lover in Shanghai, and he generated the idea of helping male sex workers at first.