What harm would come to heterosexual Americans if same-sex couples were allowed to marry? The question seemed key to the marriage equality debate recently argued in the Supreme Court.

Republicans in the South this week offered a couple answers.

Rep. Louie Gohmert, R-Texas, told a group of Tea Party supporters on a conference call that gay marriage would be a slippery slope to polygamy and bestiality.

"When you say it's not a man and a woman anymore, then why not have three men and one woman or four women and one man?" Gohmert asked. "Or why not, you know, somebody has a love for an animal or-? There is no clear place to draw a line once you eliminate the traditional marriage."

Evan Wolfson, president of the national marriage equality campaign Freedom to Marry Inc., said those remarks show an ugly side of the opposition to gay marriage.

"I think people are appalled by his comments because he seems obsessed with sex with animals when the rest of the country is talking about loving and committed couples, the freedom to marry and the constitution," Wolfson told ABC News Thursday. "I think most Americans have recoiled from the kind of prejudice and ignorance that these remarks highlight, and that that momentum towards fairness and the freedom to marry will continue."

It isn't the first time a prominent male Republican has brought up bestiality while explaining why he believes same-sex marriage is wrong.

In a 2003 interview, former presidential primary candidate Rick Santorum mentioned it, along with pedophilia.

"In every society, the definition of marriage has not ever, to my knowledge, included homosexuality," Santorum told The Associated Press. "That's not to pick on homosexuality. It's not, you know, man on child, man on dog, or whatever the case may be. It is one thing."

The remarks immediately garnered backlash from critics who claimed Santorum, who said Wednesday he is considering another presidential run in 2016, had placed those acts on the same moral level.

During his run for the Republican nomination for president in 2012, Santorum tried to turn the remarks around, saying he had differentiated them, not linked them. But critics didn't accept his explanation.

Gay rights activist Dan Savage was not convinced and continued with his efforts to undermine Santorum in the name of equal rights.

The second explanation for opposition to gay marriage this week came from Sue Everhart, head of the Georgia Republican Party. Everhart declared gay marriage "not natural" and predicted it would lead to Americans engaging in sham weddings to obtain benefits.

"You may be as straight as an arrow, and you may have a friend that is as straight as an arrow," Everhart told the Marietta Daily Journal. "Say you had a great job with the government where you had this wonderful health plan. I mean, what would prohibit you from saying that you're gay, and y'all get married and still live as separate, but you get all the benefits? I just see so much abuse in this, it's unreal. I believe a husband and a wife should be a man and a woman, the benefits should be for a man and a woman. There is no way that this is about equality. To me, it's all about a free ride."

An opinion piece in the Atlanta Journal Constitution satirized Everhart's comments.

"Sham marriages, of course, would be an entirely new and different thing in the human experience," wrote political columnist Jim Galloway. "Lord knows how we could cope."

Wolfson also questioned Everhart's reasoning.

"There's nothing to stop people right now from entering into marriages for whatever reason," he said. "The only people who are stopped from entering into marriage are loving and committed couples who happen to be gay."

Opposition to gay marriage has been on a fast decline in the past decade.

Two Republican senators have, in recent weeks, come out in support of gay marriage, but the issue largely remains divided along party lines.

Traditional marriage advocate Joseph Backholm told ABC News in the week leading up to the Supreme Court arguments that gay marriage would hurt America's children because, he believed, they need both a male and female role model.

"If you go on the street and just start asking people at random, 'Do you think it's good for a child to have a mother and father?' virtually everyone will say yes to that question," Backholm said in March. "Boys need fathers. Girls need mothers. And the converse is true as well."