Pope Francis has urged the Catholic Church to "move forward" as a review of teaching on the family got under way amid unprecedented controversy over its attitude to homosexuality.
Saying the Church was "not a museum to keep or preserve", the Argentinian pontiff urged clerics debating a series of thorny social and religious issues in a synod on Monday (local time) to do so in a spirit of "solidarity, courage and humility".
"[The synod] is a place where the holy people of God move forward," he told the first working session of a three-week gathering that will pit conservatives and reformers against each other over issues including communion for remarried divorcees and cohabitation, as well as attitudes to gay believers.
The Pope's comments echoed his words on Sunday when he said the Church must have "its doors open to welcome all those who knock" and not "point the finger in judgment" of others.
At the same time, Francis also said traditional marriage between heterosexual couples should be defended – a view he reiterates frequently, not just because he needs to reassure conservative clerics.
"The emotional intensity of the synod is amped up because of perceptions that the Pope's position is still a work in progress," Vatican watcher John Allen said, predicting a stormy synod.
Adding to the sense of a wind of change blowing through Church corridors, a newly-founded global network of lesbian, gay, bisexual, transgender and intersex Catholics on Monday published an appeal to synod members to find "new ways of celebrating the family."
The Global Network of Rainbow Catholics, made up of believers from 30 countries, said it wanted to help Church decision-makers understand the issues surrounding sexual minorities.
The synod is the second and final round of a review initiated by Francis.
During last year's first round, language that would have seen the Church recognise the value of loving same-sex relationships was excised from the final working document that forms the basis for the talks here.