Pope Francis became the first pontiff to endorse same-sex civil unions on Wednesday, sparking cheers from gay Catholics and demands for clarification from conservatives given the Vatican’s official teaching on the issue.

The papal thumbs-up to same-sex civil unions came midway through the feature-length documentary ‘Francesco’ that had its debut screening at the Rome Film Festival on Wednesday.

The film, which includes fresh interviews with the pontiff, looks into the issues that mean the most to Pope Francis, including the environment, poverty, migration, racial and income inequality, and the people most affected by discrimination.

“Homosexual people have the right to be in a family. They are children of God,” Francis said in one of his sit-down interviews for the film. “What we have to have is a civil union law; that way they are legally covered.”

ILGA Europe, an association that promotes the interests of LGBTI people, gave the pontiff’s words a cautious welcome.

“In the context where there is so much polarisation and scapegoating of LGBTI people, often endorsed and stoked by religious leaders, Pope Francis’ statement on same-sex unions is to be welcomed and should be carefully listened to,” the organisation said on Twitter. “We will monitor closely to see in how far the statement will be picked up by the churches and will lead to real change for LGBTI people and their families.”

The Rev. James Martin, a Jesuit who has sought to build bridges with gays in the church, praised the comments as “a major step forward in the church’s support for LGBT people.”

“The pope’s speaking positively about civil unions also sends a strong message to places where the church has opposed such laws,” Martin said in a statement.

However, US conservative Bishop Thomas Tobin of Providence, Rhode Island, called for clarification. “The pope’s statement clearly contradicts what has been the long-standing teaching of the church about same-sex unions,” he said in a statement. “The church cannot support the acceptance of objectively immoral relationships.”

Catholic teaching holds that gays must be treated with dignity and respect but that homosexual acts are “intrinsically disordered.” A 2003 document from the Vatican’s doctrine office stated the church’s respect for gays “cannot lead in any way to approval of homosexual behavior or to legal recognition of homosexual unions.”

Doing so, the Vatican reasoned, would not only condone “deviant behavior,” but create an equivalence to marriage, which the church holds is an indissoluble union between man and woman.

That document was signed by the then-prefect of the office, Cardinal Joseph Ratzinger, the future Pope Benedict XVI and Francis’ predecessor.

While serving as archbishop of Buenos Aires, Francis endorsed civil unions for gay couples as an alternative to same-sex marriages. However, he had never come out publicly in favour of civil unions as pope.

Director Evgeny Afineevsky had remarkable access to cardinals, the Vatican television archives and the pope himself. He said he negotiated his way in through persistence, and deliveries of Argentine mate tea and Alfajores cookies that he got to the pope via some well-connected Argentines in Rome.