Using condoms may sometimes be justified to stop the spread of Aids, Pope Benedict says in a new book, in a major shift that relaxes one of the Vatican's most controversial positions on their use to combat the disease.

The pope's words in the book to be published on Tuesday -- while limited in scope and which do not change the Catholic ban on contraception -- were nonetheless greeted as a breakthrough by dissident Catholics, Aids workers and commentators.

"It is a marvellous victory for common sense and reason, a major step forward towards recognising that condom use can play a vital role in reducing the future impact of the HIV pandemic, said Jon O'Brien, head of the US group Catholics for Choice.   

In the 219-page book, "Light of the World", the pope also speaks frankly about the possibility that he could resign for health reasons and defends wartime pontiff Pius XII against Jewish accusations that he turned a blind eye to the Holocaust.   

He says scandals of sexual abuse of minors by priests were "an unprecedented shock", even though he had followed the issue for years, and says he can understand why people might quit the Church in protest.

But it is the section on condoms in the book -- a long interview with German Catholic journalist Peter Seewald -- that marked a crack in the once tightly shut door of Church policy.

He cites the example of the use of condoms by prostitutes as "a first step towards moralisation", even though condoms are "not really the way to deal with the evil of HIV infection".   

The original German text and the French and English  versions of the book refer to a male prostitute but an excerpt in Italian in the Vatican newspaper uses female prostitute.        

While some Roman Catholic leaders 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.   

The leading Italian newspaper Corriere della Sera said the time was "ripe" for such a papal opening and even the conservative Il Giornale ran an opinion story headlined: "We are all sinners, the Church cannot be made of stone".
   

Benedict made clear the comments were not intended to weaken the Church's fundamental opposition to artificial birth control, a source of grievance to many Catholics.   

Last year, the pope caused an international uproar when he told journalists accompanying him to Africa that condoms should not be used because they could worsen the spread of Aids.

He says that the "sheer fixation on the condom implies a banalisation of sexuality" where this is no longer an expression of love "but only a sort of drug that people administer to themselves".   

The Church had been saying for decades that condoms are not even part of the solution to fighting Aids, even though no formal position on this existed in a Vatican document.
 - Reuters