Pope Benedict used his annual Christmas message to denounce gay marriage, saying that it destroyed the “essence of the human creature.”

In one of his most important speeches of the year, the Pope stressed that a person’s gender identity is God-given and unchangeable. As a result, he sees gay marriage as a “manipulation of nature.”

"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," he said at the Vatican on Friday. "They deny their nature and decide that it is not something previously given to them, but that they make it for themselves."

The Pope has said that gay marriage, like abortion and euthanasia, is a threat to world peace.