VATICAN CITY (AP) â€” Using a condom is a lesser evil than transmitting HIV to a sexual partner â€” even if that means a woman averts a possible pregnancy, the Vatican said Tuesday, signaling a seismic shift in papal teaching as it explained Pope Benedict XVI's comments.

The Vatican has long been criticized for its patent opposition to condom use, particularly in Africa where AIDS is rampant. But the latest interpretation of Benedict's comments about condoms and HIV 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.

â€œThis is a game-changer,â€ said the Rev. James Martin, a Jesuit editor and writer. â€œBy acknowledging that condoms help prevent spread of HIV between people in sexual relationships, the pope has completely changed the Catholic discussion on condoms.â€

The change came on a day when U.N. AIDS officials announced that the number of new HIV cases has fallen significantly â€” thanks to condom use â€” and a U.S. medical journal published a study showing that a daily pill could help prevent spread of the virus among gay men.