In his message for the World Day of Peace, Pope Benedict XVI suggested that gay marriage is an attempt to harm society.

The 46th annual World Day of Peace takes place on January 1.

In a lengthy message posted on the Vatican's website in 8 different languages, the head of the Roman Catholic Church called heterosexual unions the “natural structure of marriage.”

“There is also a need to acknowledge and promote the natural structure of marriage as the union of a man and a woman in the face of attempts to make it juridically equivalent to radically different types of union; such attempts actually harm and help to destabilize marriage, obscuring its specific nature and its indispensable role in society,” Benedict wrote.

“These principles are not truths of faith, nor are they simply a corollary of the right to religious freedom. They are inscribed in human nature itself, accessible to reason and thus common to all humanity. The Church's efforts to promote them are not therefore confessional in character, but addressed to all people, whatever their religious affiliation. Efforts of this kind are all the more necessary the more these principles are denied or misunderstood, since this constitutes an offence [sic] against the truth of the human person, with serious harm to justice and peace.”

(Related: Pope Benedict XVI calls on the French church to fight gay marriage.)