As HIV/AIDS becomes more prevalent among the gay population on the mainland, some experts have joined the gay community in calling for the legal recognition of same-sex marriage as a means of curbing the infection.

Although the rate of HIV infection is 0.05 percent nationwide, gay men have been the hardest hit by the sexually transmitted disease, experts warned ahead of this year's World AIDS Day, which fell on Wednesday.

In some cities, nearly one out of five is HIV positive in the gay community, experts said.

"To legalize same-sex marriage could help stabilize and sustain gay relationships, thereby lowering the risk of contracting HIV/AIDS," said Zhang Beichuan, a professor at Qingdao University and an outspoken gay rights advocate.

In the meantime, the government continues to work hard to reach vulnerable groups, particularly gay men, and to provide safe sex education and free condoms, said Hao Yang, deputy director of the disease prevention and control bureau under the Ministry of Health.

While government programs currently reach 90,000 gay men a month, Hao said it was insufficient.

Among the gay community, many back Zhang's view on legalizing same-sex marriage. Two gay men, Zhang Zhen and Ying Zi (both aliases) demonstrated their support on Nov 20 by holding a wedding ceremony attended by 300 guests.

The pair were married at a nightclub in Changzhou city of East China's Jiangsu province, Modern Express reported on Sunday.

"Even though we did not have legal marriage documents, our civil wedding ceremony was blessed by so many friends that it will always remind us of our love and the responsibility of being loyal to each other," the paper quoted Zhang Zhen, 40, as having said.

The lack of legal recognition for same-sex marriage is partially responsible for members of the gay community having multiple sexual partners, which increases the risk of HIV infection, Zhang Beichuan said.

In Southwest China's Chongqing municipality, for example, the prevalence of HIV among gay men almost doubled from 10.6 percent in 2006 to 19.2 percent in 2009, official statistics show. Similar increases have been reported in other cities.

The Ministry of Health claims there are currently 5 to 10 million homosexuals in China, but experts say that is a conservative estimate and the real number is around 40 million.

Despite the call to legalize same-sex marriages, more than 80 percent of homosexuals in China are already in heterosexual marriages, Zhang Beichuan said, adding that gay men in these marriages place their wives at risk of infection.

Even if same-sex marriage receives legal recognition, Zhang said he did not see a lot of gay men openly getting married, due to the stigma attached to homosexuality.