Pope Francis says the Church is “not a museum” but a place for progress, as members of a key synod on the family began the first day of what promises to be a heated debate.

The Pope urged a spirit of “solidarity, courage and humility” as the Catholic Church’s conservative and liberal wings began tackling hot-button topics from communion for remarried divorcees to acceptance of homosexuality.

The 78-year old reminded red-hatted cardinals and purple-sashed bishops that the Church was “not a museum to keep or preserve. It’s a place where the holy people of God move forward”.

• Pope Francis opens synod on family amid controversy
• Pope Francis embarrasses US in speech to Congress
• Pope Francis warns of ‘urgent’ risk to the planet

At the opening synod mass on Sunday, the Pope had offered encouragement to both camps, defending marriage and heterosexual couples but also insisting the Church must have “its doors open to welcome all those who knock”.

In an apparent boost to those who would have priests take a more merciful and inclusive approach to homosexuals, he said the Church must not “point the finger in judgement” of others, because doing so would “betray its mission”.

But he has also said traditional marriage between heterosexual couples should be defended.

Pope Francis insists the Church must have “its doors open to welcome all those who knock”. Photo: Getty

“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 wrote on Cruxnow, a news website dedicated to the Catholic community.

“Whenever topics such as homosexuality and divorce are on the docket, feelings will run strong.

“What’s new now is a sense, however exaggerated, that movement might actually be possible.

“That’s elicited strong passions both from those who see such movement as desirable, and those who view it as alarming.”

Balancing act for the Pope

The synod is the second and final round of a review of Catholic teaching on the family.

The gathering of 360 participants was overshadowed this weekend by the bombshell announcement by a Polish priest, Krzystof Charamsa, an official at the Vatican, that he is a practising homosexual with a partner.

The Vatican’s ire — which saw Mr Charasma fired from his post — contrasted with the news of the Pope’s still close relationship with an old Argentinian friend and his gay partner, who were received and hugged by pontiff in the US last month.

“After his example, whatever the outcome of the synod it will be impossible for a priest not to welcome homosexual couples as the pope has [been] … making them feel at home and gradually but progressively innovating Church mentality,” said religious expert Piero Schiavazzi in the Italian edition of the Huffington Post.

He warned, however, that bringing the synod’s opposing sides together on such issues was unlikely in the extreme.

“It would be easier to get Vladimir Putin and Barack Obama to agree … than cardinals Camillo Ruini and Walter Kasper,” he said, referring to a staunch Italian conservative and a German liberal said to be close to Francis.

Homosexuality is just one of a wide range of topics to be discussed at the synod, and some prelates have called for it not be included in the program, according to Church sources.

Mr Allen said the Pope wants other threats to the family to be discussed, from “unemployment to war, environmental calamities, a culture of exaggerated individualism and consumerism, neglect of both children and the elderly”.

“In his mind, the synod would likely be a failure if it doesn’t get around to considering those topics. If recent experience is any guide, the Pope may have his work cut out for him,” he said.