VATICAN CITY (AP) — Pope Francis says he is looking for a "sincere, open and fraternal" debate about divisive family issues that opens Sunday with progressives hoping for change and conservatives intent on keeping the status quo.

Francis made a cameo appearance Saturday at a twilight prayer vigil in St. Peter's Square on the eve of a two-week meeting of bishops aimed at making the church's teaching on sex, marriage, divorce and homosexuality relevant to today's Catholics.

Francis said he wanted the bishops to listen — really listen to what the people of God are saying — and then engage in a "sincere, open and fraternal" debate that will respond to the "epochal changes" that families are living through today.

Francis set the stage for a wide-ranging debate when he decided last year to send a 39-point questionnaire to bishops' conferences around the world, seeking input from ordinary Catholics about their acceptance of church teaching on a host of issues related to Catholic family life.

The surveys confirmed that the vast majority of Catholics ignored and rejected church teaching on sex and contraception. The responses also said the church must develop a pastoral plan to minister to gays in civil unions and to children being raised in such families, making the synod the first time the Vatican is addressing homosexuality on a pastoral level.

Church reform groups said such honest responses were reason to hope that under Francis, a meeting of bishops might yield some change if only for the fact that Francis has asked bishops to honestly speak their minds.

"If all Francis manages to do is encourage bishops to speak out and to say what they really think, then he will start a revolution almost by accident," said Miriam Duignan of the Wijngaards Institute for Catholic Research, a progressive British think tank.

She insisted that most bishops don't really want to preach that artificial contraception is morally indefensible or that homosexual acts are "intrinsically disordered," as church teaching holds.

"Whether it starts with priestly celibacy or attitudes toward homosexuality or birth control: Once you admit that your teaching was flawed, that it was based on flimsy premises and that you were wrong, we can start the conversation," she said.

While conservative groups say there is indeed a risk that the synod will result in merely sowing confusion over church teaching about sex and marriage, prelates participating in the synod are intent on reinforcing doctrine, not changing it.

"The synod is not meeting to create some new teaching in the church or to break with that tradition," the hard-line American Cardinal Raymond Burke told reporters this week. Rather, he said, the meeting is designed to "hold true to it ... underline it's important for our present time, and I hope that's what's going to happen."

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Associated Press religion writer Rachel Zoll contributed from New York.

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