Sociologist Mark Regnerus believes porn increases support for gay marriage among straight men.

Regnerus made headlines earlier this year when he published a widely criticized study which stated that the children of gay parents are more likely to have negative outcomes, including being on public assistance, being unemployed or in therapy as adults.

(Related: Study claiming negative outcomes for kids of gay parents called 'seriously flawed.')

In his new study, which was published last week on the conservative-leaning Witherspoon Institute's website, Regnerus argues that porn “undermines the concept that in the act of sexual intercourse, we share our 'body and whole self … permanently and exclusively.' On the contrary, it reinforces the idea that people can share their bodies but not their inmost selves, and that they can do so temporarily and (definitely) not exclusively without harm.”

Online porn watchers are “treated to a verifiable fire-house dousing of sex-act diversity.”

“Of the men who view pornographic material 'every day or almost every day,' 54 percent 'strongly agreed' that gay and lesbian marriage should be legal, compared with around 13 percent of those whose porn-use patterns were either monthly or less often than that. Statistical tests confirmed that porn use is a (very) significant predictor of men's support for same-sex marriage, even after controlling for other obvious factors that might influence one's perspective, such as political affiliation, religiosity, marital status, age, education, and sexual orientation.”

Women on the other hand, Regnerus argues, “aren't as into porn as men are … this theory is not about women.”