* Spokesman says pope not limiting use to gay prostitutes
* Says use by heterosexuals, transsexuals also justified
* Clarification needed because of translation error in book
(Adds apparent endorsement of ABC principle, IAS reaction)
By Philip Pullella
VATICAN CITY, Nov 23 (Reuters) - Pope Benedict's landmark acknowledgement that the use of condoms is sometimes morally justifiable to stop AIDS is valid not only for gay male prostitutes but for heterosexuals and transsexuals too, the Vatican said on Tuesday.
The clarification, the latest step in what is already seen as a significant shift in the Catholic Church policy, came at a news conference presenting the pope's new book: "Light of the World: The Pope, the Church, and the Sign of the Times".
In the book, a long interview with German Catholic journalist Peter Seewald, the pope used the example that a male prostitute would be justified using a condom to avoid transmitting the killer disease.
Vatican spokesman Father Federico Lombardi made the clarification because the German, English and French versions of the book used the male article when referring to a prostitute but the Italian version used the female article.
"I asked the pope personally if there was a serious distinction in the choice of male instead of female and he said 'no'," Lombardi said.
"That is, the point is it (the use of a condom) should be a first step towards responsibility in being aware of the risk of the life of the other person one has relations with," he said.
"If it is a man, a woman or a transsexual who does it, we are always at the same point, which is the first step in responsibly avoiding passing on a grave risk to the other.
The church had been saying for decades that condoms were not even part of the solution to fighting AIDS, even though no formal policy on this existed in a Vatican document.
The late Cardinal John O'Connor of New York famously branded the use of condoms to stop the spread of AIDS as "The Big Lie".
STEP TOWARDS MORALISATION
In the book, the pope says the use of condoms could be seen as "a first step towards moralisation", even though condoms are "not really the way to deal with the evil of HIV infection".
After the pope first mentions that the use of condoms could be justified in certain limited cases, the author, Seewald asks: "Are you saying, then, that the Catholic Church is actually not opposed in principle to the use of condoms?"
The pope answers: "It of course does not regard it as a real or moral solution, but, in this or that case, there can be nonetheless, in the intention of reducing the risk of infection, a first step in a movement toward a different way, a more human way, of living sexuality."
In the book and through Lombardi's comments, the pope seemed to be giving a cautious, qualified endorsement of the "ABC principle" (Abstinence-Be faithful-Condom) espoused by many governments and health organisations on preventing AIDS.
In the book, he says that while ABC was developed in "the secular realm", he uses the example himself to introduce his own comments on condoms being sometimes justified.
While not changing the Catholic ban on contraception -- the comments on condoms were nonetheless greeted as a breakthrough by liberal Catholics, AIDS activists and health officials.
"For the first time the use of condoms in special circumstances was endorsed by the Vatican and this is good news and good beginning for us," said Margaret Chan, director-general of the World Health Organisation.
The International AIDS Society welcomed the pope's comments as a "step in the right direction" but called on him to do more.
"While I appreciate this is a significant shift in policy by the pope, there is still a long way to go in convincing the Catholic Church that condom usage is key to the elimination of the HIV virus, which currently claims two million lives every year," IAS President Elly Katabira said in Geneva.
While some Roman Catholic leaders and theologians have spoken about the limited use of condoms to stop the spread of HIV/AIDS as the lesser of two evils, this is the first time the pope has mentioned the possibility. (Writing by Philip Pullella; additional reporting by Tom Heneghan in Paris and Kate Kelland in London, editing by Ralph Boulton and Mark Heinrich)
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