03/23/2012 05:12 pm ET Updated Feb 02, 2016

Is the Sexual Promiscuity of Straight Men a Reason to Oppose Gay Marriage?

Earlier this week, I moderated a debate here at Boston College Law School offering a prominent opponent of gay marriage an opportunity to articulate why gay men and lesbians should not be permitted to wed. His key point: that straight men are too promiscuous to be trusted. Really.

The future of gay marriage in this country may turn on whether that's a rational argument.

Some background may be necessary. If this year's big Supreme Court case is the fight over the Affordable Care Act, next year's is likely to be gay marriage. The Ninth Circuit Court of Appeals recently struck down California's ban on gay marriage, and in a few days the First Circuit Court of Appeals in Boston hears an appeal of lower court rulings striking down the federal Defense of Marriage Act (DOMA), which defines marriage as between one man and one woman. Either case could be the vehicle for the Supreme Court to decide the constitutionality of limits on gay marriage.

The legal issue in both cases would be whether the limits on marriage can meet the appropriate level of judicial scrutiny. The Obama administration has said that it now believes restrictions on same-sex marriage should receive "heightened scrutiny," like government limits based on sex or race. This is why the president has announced that his administration will not defend DOMA in court.

But making gay marriage depend on the Court applying heightened scrutiny is a long shot. In the Supreme Court's two most recent gay rights cases, Romer v. Evans in 1996 (striking down an anti-gay law in Colorado) and Lawrence v. Texas in 2003 (striking down the state's criminalization of gay sex), Justice Kennedy wrote the opinion for the Court applying so-called "rational basis" review. It is unlikely he is going to change his mind now.

But there is hope. Usually, a court using rational basis review will uphold governmental restrictions. In Romer and Lawrence, however, Kennedy avoided the question of whether sexual orientation should receive heightened scrutiny by applying a more searching kind of rational basis review -- one that looked carefully at the motivations behind the law and asked whether, on balance, they made sense or in reality were based on anti-gay animus. This is what Kennedy is likely to do in a gay marriage case.

So would the arguments of gay marriage opponents meet this level of rational basis review?

In the debate, Jordan Lorence, the Senior Vice President of the Alliance Defense Fund, argued that the main reason we have marriage is not to recognize emotional ties or validate meaningful relationships. Rather, the real reason is to protect society from the promiscuity of straight men. When men and women find themselves in close proximity, he argued, they produce children. It's the nature of men to want to have sex. Marriage is a way to constrain these urges and to channel them into long-term, exclusive commitments so that the children produced have a stable family structure. He bolstered his argument by referencing the decay of the traditional family in the "inner city," and quoting then-candidate Barack Obama's 2008 speech on the need for black men to be good fathers.

If we ignore the the race-based stereotypes implicit in his critique, we are left with an assertion that straight men cannot be trusted with their powerful sexual urges. We need the institution of marriage to constrain them. (Lorence is not alone in this argument, by the way. New York's highest court held in 2006 that marriage could be restricted to straight couples because "it is more important to promote stability, and to avoid instability, in opposite-sex than in same-sex relationships," in part because straight relationships "are all too often casual or temporary.")

This does not seem like a rational argument to me, and not just because it's more than a little bizarre to base an argument about gay marriage on the sexual proclivities of straight guys. Taken seriously, the argument overstates the power of marriage to constrain the urges of straight men (consider Bill Clinton, for example), and understates the power of marriage to validate and acknowledge loving, committed relationships between two people.

But more importantly, the argument misses the point. The crucial question that the Supreme Court must answer is not whether it is rational to award the marriage right to straight couples but whether it is irrational to exclude same-sex couples from the marriage right. And the proclivities of straight men are neither here nor there in that analysis. You cannot judge whether denying gay marriage makes sense by talking about people (straight couples) who will not be affected at all.

Unless, of course, you believe that recognizing same-sex marriages will make straight men even more promiscuous or less likely to be good fathers. I am left wondering if that is the unspoken fear of many gay marriage opponents -- that men in straight marriages will find the lure of gay marriage so tempting that they abandon their wives and children. Does that sound rational to you?