Rick Santorum on Wednesday conceded during a CNN Piers Morgan Tonight interview that he believes being gay is a 'sin.'

The 53-year-old candidate for the 2012 GOP presidential nomination has previous said he has gay friends who respect his opinion that marriage should remain a heterosexual union.

When host Piers Morgan asked, “Do you think homosexuality is a sin?” Santorum said as a politician he wasn't in a position to answer the question. But Morgan pressed on, saying the American voters deserve “an honest answer to a straightforward question.”

“Of course, the Catholic Church teaches that homosexuality is a sin. I'm a Catholic and I subscribe to the Catholic Church's teaching,” Santorum answered, then added: “But that's not relevant from the standpoint of how I view these issues from a public policy point of view.”

Later, Santorum said he would help one of his four sons through “a difficult and troubling time” if he told him he was gay.

“I guess one of the reasons it's so troubling and difficult for people to come out is because of the level of bigotry that's out there against them,” Morgan said. “And I have to say that your views you've espoused on this issue are bordering on bigotry. Aren't they?”

“No,” a flummoxed Santorum answered, “I think just because we disagree on public policy, which is what the debate has been about which is marriage, doesn't mean that it's bigotry. Just because you follow a moral code that teaches that something's wrong doesn't mean …. Are you suggesting that the Bible and that the Catholic Church is bigoted?” (The video is embedded in the right panel of this page.)