The new study, which was funded by conservative groups such as the Witherspoon Institute and the Bradley Foundation, has drawn national media attention because it was performed by Mark Regnerus, a sociology professor at the University of Texas at Austin whose qualifications outstrip previous "experts" touted by same-sex marriage opponents. Opponents of same-sex marriage have had great success exploiting conservative religious and cultural attitudes towards homosexuality in referendums and ballot measures. But in they've struggled in court, where they've lacked reputable social science justifications for their views on same-sex marriage. When compelled to prove that withholding marriage rights from two consenting adults of the same gender is a legitimate government interest, they've been armed with little more than their own assumptions.

Anti-marriage equality activists hope the Regnerus study will change the game. According to Regnerus, who described his results at Slate, "the children of women who’ve had same-sex relationships" were "more apt to report being unemployed, less healthy, more depressed, more likely to have cheated on a spouse or partner, smoke more pot, had trouble with the law, report more male and female sex partners, more sexual victimization, and were more likely to reflect negatively on their childhood family life, among other things." "The children of fathers who have had same-sex relationships," Regnerus writes, "fare a bit better."

But it's still just one study, and the evidence on the other side of the ledger is strong. The American Psychological Association has long maintained, on the basis of decades of research, that gays and lesbians make just as good parents as heterosexuals, and isn't backing down from that.

Supporters of marriage equality, such as Jim Burroway, editor of Box Turtle Bulletin, have already outlined other serious objections to the new study.