At Pope Benedict XVI's request, the Vatican is preparing a document about condom use by those with AIDS, a top cardinal said in a published interview.

"Soon the Vatican will issue a document about the use of condoms by persons who have grave diseases, starting with AIDS," Cardinal Javier Lozano Barragan, who is in charge of the Vatican's health care ministry, was quoted as saying in Sunday's La Repubblica newspaper.

"My department is carefully studying it, along with scientists and theologians entrusted with drawing up a document about the subject that will soon be made known," the Mexican cardinal said.

"It is Benedict XVI who asked us for a study on this particular aspect of using a condom by those afflicted with AIDS and by those with infectious diseases," he said.

There was no official comment Monday from the Vatican. Lozano Barragan was unavailable for comment despite repeated attempts by The Associated Press to reach him.

The Vatican opposes the use of condoms as part of its overall teaching against contraception and advocates sexual abstinence as the best way to combat the spread of the HIV virus which causes AIDS.

Last week, retired Milan Cardinal Carlo Maria Martini, a one-time papal contender, said in comments published in Italian newsweekly L'Espresso that condoms were the "lesser evil" in combatting the spread of AIDS.

Asked if he shared Martini's idea about condoms, Lozano Barragan said: "It is a very difficult and delicate subject which warrants prudence." He said he preferred not to comment on Martini's remarks, as "to not anticipate the study."

The comments by Martini, who noted that it is one thing to condone a lesser evil in such cases, and quite another for the church to publicly promote condom use, echoed those of other churchmen, including Belgian Cardinal Godfried Danneels.

Lozano Barragan has also said in past comments that condoms could sometimes be condoned, such as when a woman can't refuse her HIV-positive husband's sexual advances.

In the La Repubblica interview, Lozano Barragan was asked about Martini's suggestion that unmarried women could carry frozen embryos to term if the alternative is letting them die in the freezers of fertility clinics.

Church teaching holds that all procreation must take place within marriage; the Vatican also opposes many assisted fertility procedures.

"It is life which must prevail, and we need legislative frameworks which would allow evaluation case by case," Lozano Barragan said about the frozen embryos.

As for abandoned children, the cardinal said that although "it would be always ideal to give them a father and a mother." He added that "even singles" could adopt, "but with much prudence, and ruling out homosexuals" as adoptive parents.