Political theorist Sherif Girgis, a leading academic critics of same-sex marriage, has an interesting article criticizing me and other scholars who argue that courts should invalidate laws banning same-sex marriage because they discriminate on the basis of sex. The sex discrimination argument is just one of several rationales for striking down laws banning same-sex marriage. But in my view, it is also the best.

To his credit, unlike most other opponents of same-sex marriage, Girgis recognizes that laws banning it do indeed discriminate on the basis of gender, because they “require state officials to consider people’s sex” in determining who is allowed to marry whom. He rejects the argument that these laws are nondiscriminatory because they treat both sexes equally. As he notes “the interracial marriage ban in Loving v. Virginia was defended on similar grounds, as applying equally to blacks and whites.” He points out that a law banning same-sex marriage “involves treating sex as Virginia’s ban in Loving had treated race.”

But Girgis argues that laws banning same-sex marriage should not be subject to the same kind of heightened “intermediate” scrutiny that courts apply to other forms of sex discrimination by government, because the gender classification “used in marriage laws is meaningfully different from just about every other.” His reasons for this conclusion fall apart under inspection.

Girgis starts by claiming that laws banning same-sex marriage are different from laws banning interracial marriage because the latter were motivated by a desire to maintain “white supremacy,” while the former are not based on hostility towards any particular gender. This ignores the fact that laws banning interracial marriage and other racial classifications are still subject to strict scrutiny regardless of the state’s motives in adopting them. If, for example, a state banned interracial marriage because they want to maintain cultural diversity and worry that intermarriage will lead to assimilation of minorities, courts would surely strike it down. While white supremacy was surely the principal motive for opposition to interracial marriage throughout American history, it was not the only one. For example, some blacks opposed it because they feared it might undermine black solidarity in the face of white oppression.

Many of the Supreme Court’s cases imposing heightened scrutiny on gender classifications involve laws that were not plausibly motivated by sexism. In Craig v. Boren, the 1976 ruling where the Court first imposed such scrutiny, it struck down an Oklahoma law that forbade 18-20 year old men (but not women of the same age) from buying 3.2% alcoholic beer. It is highly unlikely that the Oklahoma state legislature of the 1970s was motivated by hostility towards men or a desire to establish a matriarchy. But the Court applied heightened scrutiny, and struck down the law nonetheless. Like racial discrimination, sex discrimination is constitutionally suspect regardless of the government’s motive for engaging in it.

Moreover, it would be a mistake to assume that sexism is irrelevant to the reasons why states have historically banned same-sex marriage. Part of the motivation for opposition to gay marriage (and homosexuality more generally) is the ways in which it undermines traditional sex roles and norms of male dominance. That clearly isn’t the only reason why people oppose same-sex marriage. It is certainly possible to oppose it while also being committed to gender equality. Similarly, some well-meaning people opposed interracial marriage without believing that one race is inherently superior to another (e.g. – because they feared that children of interracial unions would face severe social or psychological problems). But just as racism was historically a major motive for opposing interracial marriage, commitment to restrictive traditional sex roles was a major reason for denying marriage rights to same-sex couples.

Girgis also argues that laws banning same-sex marriage differ from laws banning interracial marriage because, unlike race, “[m]aleness and femaleness, and a certain social purpose, are necessarily inter-defined: one can’t even fully explain either concept without reference to the other and to a certain social good.” Maleness and femaleness are indeed “inter-defined.” But the exact same thing can be said of racial classifications. Racial distinctions make little sense, except in a society which has multiple racial groups defined with “reference to the other.” And that definition almost always involved real or imagined “social goods,” such as racial purity, social solidarity, and the well-being of children. Like gender, race is a complex combination of genuine biological differences (e.g. – in skin color) and socially determined meanings.

Similarly, Girgis claims that “[w]hat differentiates male and female are not just anatomical or genetic features, but—at a deeper level of explanation—their joint (basic) physical potential for a biological task: reproduction.” The distinctive aspects of gender are indeed relevant to reproduction. But it does not follow that this somehow justifies exempting sex discrimination in marriage laws from heightened scrutiny.

Thanks to adoption and artificial insemination, same-sex marriage is also closely connected to reproduction. Same-sex couples raise numerous children, and do so even in states where same-sex marriage is still not recognized. While the means by which they acquire custody of children differ from traditional biological reproduction, they still play much the same role in raising the next generation.

None of this indicates that there are never situations where gender classifications might be permitted even though racial ones would be forbidden. Current Supreme Court doctrine recognizes the differences between the two by holding that sex discrimination is subject only to intermediate scrutiny, while race discrimination gets strict scrutiny. But the former is still a rigorous form of heightened scrutiny, and rightly so. As in the case of racial discrimination, we have a long history of oppression based on gender. For that reason, among others, even the most well-intentioned forms of state-imposed gender discrimination are constitutionally suspect. There is no good reason to exempt laws restricting marriage from that rule.

UPDATE: Since I didn’t make this as clear as I probably should have in the original post, I should note that I am well aware that child-raising is distinct from reproduction. However, the main reason why government and society are concerned about the latter is because it results in children that require the former. Moreover, most opponents of same-sex marriage recognize that opposite-sex marriage is connected with reproduction even in cases where the spouses are unable to reproduce by traditional biological means; the connection exists because they can still raise children acquired through adoption and artificial insemination. The same is true of opposite-sex couples.

UPDATE #2: I foolishly misspelled Sherif Girgis’ last name as “Gerges” in the original version of this post. I am very sorry for the mistake, which has now been corrected.