Cardinal Francis George, the leader of the Catholic Church in Chicago, said this week that he believes gay marriage is not natural.

Speaking to the Chicago Sun Times, George, a longtime opponent of gay nuptials, placed his faith secondary in framing his opposition to marriage equality.

“This is first of all a rational issue before it's a faith issue,” George said. “That is, it's nature that tells us what marriage is, that in marriage, men and women aren't interchangeable.”

“We didn't invent marriage. The church didn't invent marriage. The state didn't invent marriage. Nature gives us marriage. The Chinese are not Americans, and they're not Catholic. They know what marriage is. Where did that come from?”

George continued: “In marriage, men and women do different things. They raise children differently. They contribute differently. They simply are different. It means something to be a man that's different from what it means to be a woman, and vice versa. And to deny that obvious fact is something that just puzzles me, not as a matter of faith, but it seems to me to be less than reasonable.”

A bill which seeks to legalize marriage for gay couples in Illinois stalled in the House earlier this year after it passed in the Senate on Valentine's Day. Rep. Greg Harris, the bill's champion in the House, has pledged a House vote sometime in the fall.

George said that if approved, the marriage law would mean that “people have to kind of suppress what they know about marriage, just ignore it.”