Pope Benedict XVI, the head of the Roman Catholic Church, on Friday criticized gay marriage.

In his annual Christmas address given at the Vatican, Benedict denounced such unions as a manipulation of sexual identity, the AP reported. The pope also dedicated the coming year to promoting family values.

“People dispute the idea that they have a nature, given to them by their bodily identity, that serves as a defining element of the human being,” the Holy Father said in one of his most important speeches of the year. “They deny their nature and decide that it is not something previously given to them, but that they make it for themselves.”

“The manipulation of nature, which we deplore today where our environment is concerned, now becomes man's fundamental choice where he himself is concerned.”

Benedict and the Vatican have increased their opposition as predominantly Catholic France debates the issue of gay nuptials.

(Related: Vatican criticizes French Catholic magazine's gay marriage endorsement.)

Last week, in his message for the January 1 World Day of Peace, Benedict said that marriage equality threatens justice and peace. The comments prompted a small group of activists to protest the pope's views.