Pope Francis, right, delivers his message during his weekly general audience at the Vatican on Wednesday. Francis endorsed same-sex civil unions while being interviewed for the feature-length documentary “Francesco,” which premiered Wednesday.

ROME — Pope Francis became the first pontiff to endorse same-sex civil unions in comments for a documentary that premiered 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 came midway through the feature-length documentary “Francesco,” which premiered at the Rome Film Festival. The film, which features fresh interviews with the pope, delves into issues Francis cares about most, 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. “You can’t kick someone out of a family, nor make their life miserable for this. What we have to have is a civil union law; that way they are legally covered.”

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 favor of civil unions as pope, and no pontiff before him had either.

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

However, conservative Bishop Thomas Tobin of Providence, R.I., 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. “The church cannot support the acceptance of objectively immoral relationships.”