Using a condom is a lesser evil than transmitting HIV to a sexual partner _ even if that means averting a possible pregnancy, the Vatican said Tuesday, signaling a seismic shift in papal teaching as it further explained Pope Benedict XVI's comments.

The Vatican has long been criticized for its patent opposition to condom use, particularly in Africa. But the latest interpretation essentially means the Roman Catholic Church is acknowledging that its long-held, anti-birth control stance against condoms doesn't justify putting someone's life at risk.

Benedict said in a book released Tuesday that condom use by people such as male prostitutes was a lesser evil since it indicated they were moving toward a more moral and responsible sexuality by aiming to protect their partner from a deadly infection.

His comments implied that he was referring primarily to homosexual sex, when condoms aren't being used as a form of contraception, which the Vatican opposes.

Questions arose immediately about the pope's intent, though, because the Italian translation of the book used the feminine for prostitute, whereas the original German used the masculine.

The Vatican spokesman, the Rev. Federico Lombardi, told reporters Tuesday that he asked the pope whether he intended his comments to only apply to male prostitutes. Benedict replied that it really didn't matter, that the important thing was the person in question took into consideration the life of the other, Lombardi said.

"I personally asked the pope if there was a serious, important problem in the choice of the masculine over the feminine," Lombardi said. "He told me no. The problem is this ... It's the first step of taking responsibility, of taking into consideration the risk of the life of another with whom you have a relationship."

"This is if you're a woman, a man, or a transsexual. We're at the same point. The point is it's a first step of taking responsibility, of avoiding passing a grave risk onto another," Lombardi said.

The clarification is significant.

UNAIDS estimates that 22.4 million people in Africa are infected with HIV, and that 54 percent _ or 12.1 million _ are women. Heterosexual transmission of HIV and multiple, heterosexual partners are believed to be a major cause of the high infection rates in Africa.

Benedict drew the wrath of the United Nations, European governments and AIDS activists when, en route to Africa in 2009, he told reporters that the AIDS problem on the continent couldn't be resolved by distributing condoms. "On the contrary, it increases the problem," he said then.

In the book, the pope was not justifying or condoning gay sex or heterosexual sex outside of a marriage. Elsewhere in it, he reaffirms the Vatican opposition to homosexual acts and artificial contraception and reaffirms the inviolability of marriage between man and woman.

But by broadening the condom comments to also apply to women, the pope is saying that condom use is a lesser evil than passing HIV onto a partner.

While that concept has long been a tenet of moral theology, the pope's book "Light of the World" _ a series of interviews with a German journalist _ marked the first time a pope had ever publicly applied the theory to condom use as a way to fight HIV transmission.

Monsignor Jacques Suaudeau, an expert at the Vatican's bioethics advisory board, said the pope was articulating the idea in church teaching _ long practiced by some church officials with regards to condoms _ that there are degrees of evil.

"Contraception is not the worst evil. The church does not see it as good, but the church does not see it as the worst," he told The Associated Press. "Abortion is far worse. Passing on HIV is criminal. That is absolute irresponsibility."

He said the pope broached the topic because questions about condoms and AIDS persisted.

"This pope gave this interview. He was not foolish. It was intentional. He thought that this was a way of bringing up many questions. Why? Because it's true that the church sometimes has not been too clear," Suaudeau said.

Luigi Accatoli a veteran Vatican journalist who was on the Vatican panel to launch the book put it this way:

"He spoke with caution and courage of a pragmatic way through which missionaries and other ecclesial workers can help to defeat the pandemic of AIDS without approving but also without excluding _ in particular cases _ the use of a condom," Accatoli said.

___

Associated Press reporters Victor L. Simpson in Rome and Jason Straziuso in Nairobi contributed to this report.