Critics of gay marriage have long argued that approval of the issue would open the flood gates to things like polygamy. Liberal law professor Kent Greenfield of Boston College Law School agrees.

Eric Owens of The Daily Caller reports.

Leftist law professor says gay marriage likely to lead to legalized incest, polygamy

In the wake of the U.S. Supreme Court’s two recent rulings validating gay marriage, a Boston College Law School professor has come out and admitted what gay marriage adversaries have long argued: incest and polygamy are just around the bend.

“You know those opponents of marriage equality who said government approval of same-sex marriage might erode bans on polygamous and incestuous marriages?” asks the professor, Kent Greenfield. “They’re right.”

In a piece at the website of The American Prospect, the Catholic law school prof then goes on to challenge gay marriage supporters to differentiate totally acceptable gay and lesbian marriages from various forms of communal marriage and sibling love.

“The left is in this bind in part because our arguments for expanding the marriage right to same-sex couples have been so compelling,” Greenfield brags proudly. “Marriage, we’ve said, is about defining one’s own family and consecrating a union based on love. We’ve voiced these arguments in constitutional terms, using claims arising from the doctrines of ‘fundamental rights’ and equal protection.”

After a discussion of the famous sodomy case, Lawrence v. Texas, which waxes poetically about the “right to define one’s own concept of existence,” Greenfield then pops the question: under such a legal rubric, “why can’t people in polyamorous relationships claim that right as well?”