A Gallup poll confirmed in July that approximately half of all Americans support nationwide legalization of same-sex marriage. With the repeal of the Defense of Marriage Act, it appears that same-sex marriage across the United States is as inevitable as interracial marriage was prior to the watershed case Loving v. Virginia. An issue that has received far less national attention, however, is the issue of cousin marriage. Marriage between first cousins, like same-sex marriage, faces a flaw inherent to federalism: certain states permit it while others prohibit it. Like same-sex marriage and interracial marriage, cousin marriage involves two adults consenting to enter a marriage contract. Why, then, does marriage between first cousins not receive the same support as same-sex marriage or interracial marriage? I contend that supporting same-sex marriage or interracial marriage and opposing first cousin marriage are incongruous positions to hold. The primary argument against first cousin marriage is biological. Opponents assert that children of first cousins are more susceptible to birth defects that arise from recessive traits such as genetic disorders. This argument falls apart for various reasons. Several studies demonstrate that the increased risk of defects among children born to consanguineous parents is small. An American research panel assembled by the National Society of Genetic Counselors reported that the increased risk of serious birth defect in children born to related parents is insignificant. British researchers leading the Born in Bradford project corroborated these conclusions, reporting that the risk of birth defects increases from 3 percent to 6 percent for children of related parents. Meanwhile, mothers over the age of 40 experience significant increases in the likelihood that their offspring will be born with birth defects. Persons with genetic disorders such as achondroplasia, hemophilia, or Huntington’s disease have a 50 percent chance of producing children with their abnormal genes. Compare these high percentages with the marginal increase in risk of birth defects for consanguineous parents. I don’t foresee any United States legislature denying older women the right to marry, or denying persons with the aforementioned genetic disorders the right to enter a marriage with another consenting adult. The argument that first cousin marriage should not be legalized nationwide because of marginal increases in the likelihood of producing children with birth defects is, therefore, untenable. Furthermore, this argument operates under the presumption that the purpose of marriage is procreation. There are plenty of reasons that two first cousins, as any other adults, would consent to entering a marriage contract outside of procreation. The birth defect argument fallaciously implies that first cousins who choose to marry will produce children. According to the Centers for Disease Control, 40.7 percent of births occur outside of marriage. It appears that the issue that detractors of first cousin marriage have lies with reproduction and not marriage. Again, I don’t foresee any United States legislature denying two consenting adults the right to reproduce. And then there’s the “ick” factor, which has also been used in opposition of interracial marriage and same-sex marriage. The term “incest” is used to marginalize consanguineous couples that mutually consent to marry in the way that “sodomy” is used to marginalize same-sex couples. It’s also a term that carries different meanings in different cultural contexts and should not be used to disparage first cousin couples. Intrinsically, “incest” carries neither a positive or negative meaning. To defend interracial marriage or same-sex marriage while opposing consanguineous marriage on the basis of the “ick” factor is inconsistent. In a world where there exist countries in which over half of all married couples are cousins, it’s odd that the United States remains the only Western nation wherein laws against first cousin marriage exist. If the “two consenting adults” argument is to be applied to interracial marriage and same-sex marriage, then there’s no reason that consanguineous marriage should not be uniformly legal across America. Nazar Aljassar is a Viewpoint columnist for The Cavalier Daily. His columns run Fridays.