The pope has officially endorsed same-sex civil unions for the first time since becoming pontiff.

In ‘Politics and Society,’ a book containing 12 printed conversations between Pope Francis and French Sociologist Dominique Wolton, the pope shared his feelings on marriage equality.

“’Marriage between people of the same sex? ‘Marriage’ is a historical word,” he said. “‘Always in humanity, and not only within the Church, it’s between a man and a woman… we cannot change that. This is the nature of things. This is how they are.” he said. “Let’s call them ‘civil unions.’ Let’s not play with the truth.”

As an archbishop in Argentina, Francis opposed same-sex marriage but compromised on civil unions, but this is the first official instance since becoming pope.

“Let’s say things as they are: Marriage is between a man and a woman. This is the precise term. Let’s call unions between the same-sex ‘civil unions.'”

Also in the book, the pope condemns teaching children about gender identity, believing it leads children to think their gender is a choice.

“It’s true that beyond it there is a gender ideology. In books, also, children are learning that they can choose their own sex,” he said. “Why is sex, being a woman or a man, a choice and not a fact of nature? This favors this mistake.”

The pope made similar comments last October, saying schools are teaching children they can “choose their gender.”

"This is against nature. It is one thing when someone has this tendency ... and it is another matter to teach this in school,” he said. "Today, in schools they are teaching this to children — to children! — that everyone can choose their gender.”

There has been no clarification on which schools the pope thinks are allegedly teaching this to children.

On LGBT issues, the pope’s views have come in a mixed bag. In June of last year, Pope Francis said gay people and marginalized communities deserve an apology from the church.

"Someone who has this condition, who has good will and is searching for God, who are we to judge?” he said. "I think the church must not only apologize ... to a gay person it offended, but we must apologize to the poor, to women who have been exploited, to children forced into labor, apologize for having blessed so many weapons" and for having failed to accompany families who faced divorces or experienced other problems.

Three months later, Pope Francis voiced support for anti-same-sex marriage protests in Mexico "in favor of family and life, which in these times require special pastoral and cultural attention around the world."