The Vatican on Tuesday launched a worldwide consultation on the new realities of family life including divorce and gay marriage as part of Pope Francis's efforts to reform the Catholic Church.
A questionnaire has been sent out to bishops around the world asking them for detailed information about "many new situations requiring the Church's attention and pastoral care".
"Concerns which were unheard of until a few years ago have arisen today as a result of different situations, from the widespread practice of cohabitation... to same-sex unions," it said.
The initiative is part of preparations for a synod of bishops next year and another in 2015 that the Vatican said will formulate "working guidelines in the pastoral care of the person and the family".
Lorenzo Baldisseri, head of the synod of bishops, told reporters that the meeting's theme "reflects very well the pastoral zeal with which the Holy Father wishes to approach the proclamation of the Gospel to the family in today's world".
He said the consultation also showed Francis, who has said the Catholic Church is too "Vatican-centric", wanted more "collegiality".
Cardinal Peter Erdo, president of the Council of the Bishops' Conferences of Europe, referred in particular to the increase in cohabiting Catholic couples who do not intend to marry, saying "the phenomenon requires a deepened reflection".
Pope Francis has signalled greater openness, an international outlook and a desire to bring the Catholic Church more in touch with the lives of ordinary people, although experts say he is unlikely to bring about major changes in doctrine.
Francis has said priests should baptise children even when the parents are not married and when asked recently about his views on gay people, he replied: "If someone is gay and seeks the Lord with good will, who am I to judge?"