Anti-gay activists have criticized Ohio Senator Rob Portman's recent endorsement of gay marriage, which he said was inspired by the coming out of his son, Will Portman, a college student.

Portman is the first GOP senator to buck the party's official stance.

(Related: Senator Rob Portman reverses course on gay marriage.)

Matt Barber of Liberty Counsel criticized Portman for trying to “accommodate his son's abhorrent lifestyle.”

“This provides us a perfect example of the danger of looking at things through the jaundiced prism of our own feelings rather than on objective truths,” Barber told Instant Analysis, formerly OneNewsNow.

“I've heard some wacky excuses by politicians for changing their minds on some of the most important moral issues facing America, but Ohio Sen. Rob Portman's rationale for flip-flopping on same-sex marriage takes the proverbial wedding cake,” editor Joseph Farah wrote.

“In case you haven't heard, his son is a homosexual.”

“I guess we should all be grateful Rob Portman's son didn't choose to become a polygamist or a serial killer,” he added.

Linda Harvey, president of the Ohio-based Mission American, called Will Portman's sexual orientation a “delusion.”

“Every person out there who claims a 'gay' identity has the ability to get married in Ohio or anywhere else now,” Harvey said. “He or she can marry someone of the opposite sex, because that's what marriage is and because a 'gay' identity is a delusion. Two men, no matter how sincere they feel, or two women, will never be a marriage. The person who believes this disorder is 'who he is,' as apparently Portman's son does, has tragically internalized a lie.”

(Related: Rob Portman warned that his gay son may die of AIDS.)