AIDS activists praise pope's condom comments November 21, 2010 -- Updated 1312 GMT (2112 HKT)

Rome, Italy (CNN) -- Pope Benedict XVI's possible shift on condom use is a "significant and positive step forward," the head of the United Nations anti-AIDS campaign said, welcoming the potentially historic remark. "This move recognizes that responsible sexual behavior and the use of condoms have important roles in HIV prevention," UNAIDS executive director Michel Sidibe said in a statement. "This will help accelerate the HIV prevention revolution," he said Saturday. The Roman Catholic Church firmly opposes artificial contraception, including condoms.

The pope caused a firestorm of protest last year when he spoke out against condoms as a way of controlling AIDS during a trip to Africa, the continent hardest hit by the disease. "You can't resolve it with the distribution of condoms," the pope told reporters in March 2009. "On the contrary, it increases the problem." But he outlined a possible exception in remarks published Saturday.

"There could be single cases that can be justified, for instance when a prostitute uses a condom, and this can be a first step towards a moralization, a first assumption of responsibility, to develop again the awareness of the fact that not all is allowed and that one cannot do everything one wants," Benedict said. "However, this is not the true and proper way to defeat the infection of HIV," he added, saying the "humanization of sexuality" was the best method. "What makes this newsworthy is that he's talking about an exception, where there were no exceptions whatsoever before," said James Martin, a New York Jesuit priest and author. "Just that the discussion is happening is significant," he added. Benedict's remarks may