Gay country music star Clay Aiken on Sunday told the leader of a Christian think tank that he would eventually be "ashamed" over his opposition to rights for LGBT Americans.

During a discussion about President Obama's support of same sex marriage, Family Research Council's Tony Perkins explained that "civil rights are rooted in natural law: Americans just don't see same sex marriage as being natural."

"When you look at [the ban on] interracial marriage, that was wrong," Perkins admitted. "There was no reason to be opposed to that because you had two people who met the definition of marriage between a man and a woman. And that's consistent with natural law, which our civil rights are based on. When you look at same sex marriage, that's counter to natural law."

"I see this as more along the lines of the abortion debate," he added. "You can make it legal, but you can't make it right. ... The key to less government is to ensure that kids have moms and dads, not just two caregivers because if it were two then three would be better. It's moms and dads."

Sitting directly next to Perkins on CBS's Face the Nation, American Idol runner-up Clay Aiken, a Southern Baptist who announced he was gay after having his first child in 2008, confronted the Family Research Council president.

"Between the time of 2003 and today, we've seen -- as we've seen with gay marriage polling -- we've seen minds changing," Aiken explained. "We've seen people become more open and understanding of homosexuality."

"I want to address the fact of what you just said here," the country star said, turning to Perkins. "When my mother married my stepfather, she went to a church -- a Baptist church -- and since she had been divorced, they wouldn't let her get married there. So, churches are able to decide who gets married in a church regardless."

"Obviously, you've got people who make the argument that interracial relationships -- back in the 70s, people made the same arguments against interracial relationships as they are making against same sex marriages today. So, I feel -- I really strongly believe in the next 20 years, we're going to look back on this and be sort of ashamed of the fact that we're against this, just as we are ashamed today that we didn't let people of different races get married."

Watch this video from CBS's Face the Nation, broadcast Mat 13, 2012.