Don’t be surprised if the Vatican begins “clarifying” these remarks soon. But here’s what’s being reported at this hour:

Pope Benedict XVI says that condom use is acceptable “in certain cases”, notably “to reduce the risk of infection” with HIV, in a book due out Tuesday, apparently softening his once hardline stance.

In a series of interviews published in his native German, the 83-year-old Benedict is asked whether “the Catholic Church is not fundamentally against the use of condoms.”

“It of course does not see it as a real and moral solution,” the pope replies.

“In certain cases, where the intention is to reduce the risk of infection, it can nevertheless be a first step on the way to another, more humane sexuality,” said the head of the world’s 1.1 billion Catholics.

The new volume, entitled “Light of the World: The Pope, the Church and the Signs of the Times”, is based on 20 hours of interviews conducted by German journalist Peter Seewald.

Until now, the Vatican had prohibited the use of any form of contraception — other than abstinence — even as a guard against sexually transmitted disease.

Benedict sparked international outcry in March 2009 on a visit to AIDS-ravaged Africa when he told reporters the disease was a tragedy “that cannot be overcome through the distribution of condoms, which even aggravates the problems.”

To illustrate his apparent shift in position, Benedict offered the example of a male prostitute using a condom.

“There may be justified individual cases, for example when a male prostitute uses a condom, where this can be … a first bit of responsibility, to re-develop the understanding that not everything is permitted and that one may not do everything one wishes,” Benedict was quoted as saying.

“But it is not the proper way to deal with the horror of HIV infection.”

Benedict reiterated that condom use alone would not solve the problem of HIV/AIDS. “More must happen,” he said.

“Becoming simply fixated on the issue of condoms makes sexuality more banal and exactly this is the reason why so many people no longer find sexuality to be an expression of their love, but a type of self-administered drug.”

Read more. And stay tuned. Meantime, you can read an excerpt from the book right here.

UPDATES & REACTION (running thread, updated periodically):

Fr. James Martin, America magazine: “Reading the entire text of the pope’s response in the copy of Light of the World we received supports the conclusion that this is a new development in the church’s approach to condoms, which had previously been ruled out. If this is so, it is a case of the ecclesia audiens, the listening church, which listens to the experience of the faithful, of theologians and of experts in various fields.” (He also links to an essay from 2000 on the topic.)

Damien Thompson, in London: “I am praying that this report is true, because the argument it attributes to the Pope is thoroughly humane and reasonable – and does not contradict the Church’s teaching against artificial birth control.”

The Anchoress: “The press loves its “Rottweiler narrative” on Benedict, but he has confounded them on it, over and over again. Sooner or later they will realize he was never the hammer they claimed he was. He has always been extremely pastoral; wedded to the truth while aware of human complexities. And here he is, proving it again…”

Dr. Janet Smith, a consultor to the Pontifical Council on the Family: “[The pope] says that the Church does not find condoms to be a ‘real or moral solution.’ That means the Church does not find condoms either to be moral or an effective way of fighting the transmission of HIV. As the Holy Father indicates in his fuller answer, the most effective portion of programs designed to reduce the transmission of HIV are calls to abstinence and fidelity. The Holy Father, again, is saying that the intention to reduce the transmission of any infection is a ‘first step’ in a movement towards a more human way of living sexuality.

Andrew Sullivan: “What this exception to the rule suggests is that sexual morality is not always black and white. Benedict has chosen a case where transmission of new life (barring a real miracle) is already impossible, and where wearing a condom (i.e. not risking infection of a sexual partner) is more responsible than not. The Vatican insists that the general doctrine remains the same.”

Cardinal Elio Sgreccia, the Vatican’s long-time top official on bioethics and sexuality:  “If Benedict XVI raised the question of exceptions, this exception must be accepted… and it must be verified that this is the only way to save life. This must be demonstrated.”

Fr. Joseph Fessio, a former student of Benedict’s, and editor of Ignatius Press: “It’s very carefully qualified. It would be wrong to say, ‘Pope Approves Condoms.’ He’s saying it’s immoral but in an individual case the use of a condom could be an awakening to someone that he’s got to be more conscious of his actions.”

Longtime Vatican observer John Allen: “Pope Benedict XVI has signaled that in some limited cases, where the intent is to prevent the transmission of disease rather than to prevent pregnancy, the use of condoms might be morally justified. While that position is hardly new, in the sense that a large number of Catholic theologians and even a special Vatican commission requested by Benedict XVI have endorsed it, this is the first time the Pope himself has publicly espoused such a view. The comments do not yet rise to the level of official church teaching, but they do suggest that Benedict might be open to such a development.”