Professor Mark Regnerus told a crowd that gay marriage will embolden straight men to demand open relationships from their girlfriends and wives.

Regnerus, an associate professor of sociology at the University of Texas at Austin, has been widely criticized for concluding in a 2012 study funded by a conservative think tank that children are negatively affected by having gay parents.

(Relate: Study claiming negative outcomes for kids of gay parents called “seriously flawed.”)

Opponents of marriage equality have used Regnerus' study, titled the New Family Structures Study, to argue in favor of prohibiting gay couples from marrying or adopting children.

“If gay marriage is perceived as legitimate by heterosexual women, it will eventually embolden boyfriends everywhere – and not a few husbands – to press for what men have always historically wanted but were rarely allowed: Sexual novelty in the form of permission to stray without jeopardizing their primary relationship,” Regnerus told a Franciscan University audience. “Discussion of openness in sexual partners in straight marriages will become more common, just as the practice of heterosexual anal sex got a big boost from the normalization of gay men's sexual behavior in both contemporary porn and in the American imagination.”