Pennsylvania Rep. Brian Sims is among the Democrats criticizing Governor Tom Corbett for comparing gay marriage to incest.

“No one, not even his own party, would argue that he's an intellectual heavyweight or even a particularly thoughtful person,” Sims wrote on his Facebook page. “The larger issue is that despite the fact that the majority of Pennsylvanians disagree with him, he continues to be the heaviest hitter in Pennsylvania's anti-equality crusade.”

By mid-afternoon Friday the Republican governor had issued a statement apologizing for remarks he had made that morning during an appearance on Harrisburg's WHP-TV.

Corbett was asked about a statement his lawyers made in a recent court filing to stop a county clerk from issuing marriage licenses to gay and lesbian couples. The lawyers argued that licenses issued to gay couples are invalid because such couples – like “12-year-olds” – can't marry.

“It was an inappropriate analogy, you know. I think a much better analogy would have been brother and sister, don't you?” Corbett, a Republican, answered with a smile.

“I don't know,” the anchor responded.

(Watch video of the interview at our video library.)

“My words were not intended to offend anyone,” Corbett said in his written apology. “If they did, I apologize.”

Vermont Governor Peter Shumlin, who chairs the Democratic Governor's Association, described Corbett's comparison as “absurd,” saying that he had “offended and demeaned” the “millions of Pennsylvania families he claims to represent.”

Democratic Congresswoman Allyson Schwartz, a gubernatorial candidate, called Corbett's statements “hateful.”

(Related: Gay marriage bill introduced in Pennsylvania House.)