For the last week of December, we’re re-posting some of our favorite posts from 2011.


Kristina Killgrove, anthropology professor at University of North Carolina, Chapel Hill, asked a great question about a set of maps posted at Move On.  The maps compare the states that allow gay marriage with the states that allow cousin marriage.  Most Americans find cousin marriage to be disturbing and testimonials from married cousins about their deteriorated family relations and social stigma attest to it.  The idea behind these maps, then, is that cousin marriage is genuinely weird or gross, and yet many states grant cousins the right to marry, but not gays and lesbians.

In fact,  emerging evidence that cousin marriages do not significantly increase the risk of birth defects suggest that the stigma and laws against cousin marriage are unwarranted.  A doctor cited in the study suggests that disallowing their marriages or rights to have children are tantamount to “eugenics or forced sterilization.”  Even if there were significantly increased risks of genetic disorders, Dr. Bittles argues, “People with severe disorders like Huntington’s disease, who have a 50 percent chance of passing it on to their offspring, are not barred from marrying because of the risk of genetic defects… so cousins should not be, either.”

In any case, U.S. aversion to cousin marriage is culturally and historically contingent.  That is, it is related to our particular time and place.  Worldwide, more than 10 percent of marriages occur between first cousins and cousin marriage, historically, has been quite desirable.

Lisa Wade, PhD is an Associate Professor at Tulane University. She is the author of American Hookup, a book about college sexual culture; a textbook about gender; and a forthcoming introductory text: Terrible Magnificent Sociology. You can follow her on Twitter and Instagram.