Last week, I critiqued the argument against same-sex marriage, set forth by Robert George, a prominent conservative professor at Princeton, and two co-authors. In essence, their argument is that same-sex couples can be excluded from marriage because the core purpose of the institution is procreation internal to the union. I asked whether the extended defense they gave succeeded and argued that it did not because of a simple flaw at its core.
The flaw is that the principle of "common procreation," as this idea is known, is overinclusive. It demeans the marriages of many opposite-sex couples who do not give birth to biological children, including infertile couples, couples who have chosen not to have children, couples who have adopted, and couples who have used reproductive technologies to create their families. My critique concluded that the capacity (or desire) to procreate is not a principled ground on which to define same-sex couples out of the institution of marriage while pretending to keep all opposite-sex couples inside it.
George and his colleagues have published a response to my critique. They contend that I have " ignored their central arguments,  made unwarranted linguistic associations,  indulged in pejorative labeling, and  studiously ignored every challenge [they] pose." I believe I understand why they feel I have missed their arguments, as my interest (stated in my critique) was in whether they had propounded a better version of the "common procreation" argument than the one offered in court by the proponents of Proposition 8, California's gay marriage ban. This interest led me to focus on one part of their argument more than on others. To be clear, however, I am not making an analytic concession—the common procreation argument is so central to their thesis that rebutting this part undermines the whole. I now take the opportunity to elaborate on this point by taking up their four objections.
In their response, George and his colleagues state that "[t]he central argument of our article is that equality and justice are indeed crucial to the debate over civil marriage law, but that to settle it—to determine what equality and justice demand, one must answer the question: what is marriage?" Their answer to this question is that marriage is "conjugal marriage," a pre-legal reality consisting of the union of one man and one woman. The co-authors note that "in making our case for conjugal marriage, we consider the nature of human embodiedness; how this makes comprehensive interpersonal unions sealed in conjugal acts possible; and how such union and its intrinsic connection to children give marriage its distinctive norms of monogamy, exclusivity, and permanence." Each and every one of these dimensions relates to the principle of "common procreation." According to the co-authors, the salient aspect of human "embodiedness" is the fact that "individual adults are naturally incomplete with respect to one biological function: sexual reproduction." The orientation toward procreation is also the quality that differentiates the sexual activity of opposite-sex couples from that of same-sex couples and affords opposite-sex couples a distinctive relationship to their biological children. Opposite-sex couples, the co-authors say, engage in "the kind of activity that is by its nature fulfilled by the conception of a child."
Given this reliance on common procreation as the foundation of heterosexual marriage, George and his colleagues must provide an answer for why opposite-sex couples who do not engage in common procreation still have what they call "true marriages." They attempt to do so but fail. Consider the case of infertile couples. The original article reassures infertile couples that their marriages are "real" by observing: "A baseball team has its characteristic structure largely because of its orientation to winning games; it involves developing and sharing one's athletic skills in the way best suited for honorably winning . . . But such development and sharing are possible and inherently valuable for teammates even when they lose their games." As I have already observed, this ostensible rescue still demeans the marriages of infertile couples by comparing them to baseball teams that not only do not win games but also cannot win games.
George and his colleagues state that I mischaracterized the core of their analogy (this is what they call "unwarranted linguistic associations"). They argue that I mistook an analogy (X is like Y) for an identity (X is like Y along all dimensions), noting that they make an appropriate qualification in the article "only a few sentences after drawing this analogy." To look at their actual qualification, however, is to see that the core of the analogy is precisely as I described it. The article states: "Although marriage is a social practice that has its basic structure by nature whereas baseball is wholly conventional, the analogy highlights a crucial point: Infertile couples and winless baseball teams both meet the basic requirements for participating in the practice (conjugal union; practicing and playing the game) and retain their basic orientation to the fulfillment of that practice (bearing and rearing children; winning games), even if that fulfillment is never reached." The qualification is that marriage and baseball are not fully analogous in that one draws its structure in part from nature while the other is wholly a social construct. Having made that distinction, the article notes convergence on a "crucial point": "infertile couples and winless baseball teams" are similar because both engage in a practice to which their organizations have a basic orientation, "even if that fulfillment is never reached."
In their response, George and his colleagues now enter a different qualification, observing that sports, unlike marriages, are "a competitive activity in which having winners and losers is inherent to the practice." (This cannot be read as a restatement of the article's original distinction between partially and wholly conventional activities, as both partially and wholly conventional activities can be competitive.) But even this freshly minted comeback is unavailing—infertile couples are still not fulfilling the supposed core purpose of marriage. Regardless of whether infertile couples are characterized as "winless" or as not having "fulfilled" the core purpose of marriage, such couples must compare unfavorably to couples who have fulfilled the supposed central object of marriage. This problem also stands as an impediment to the separate argument made in the article that infertile couples are still engaged in "conjugal" sexual activity because their "coitus" leads to a special kind of union. Why deem the sexual intimacy of an infertile couple to be a totally separate activity from the sexual intimacy of a same-sex couple, when neither results in procreation? Again, even if we accept the co-authors' answer (consummation is a symbolic "sealing" of the relationship "oriented" toward procreation), the infertile couple is still not fulfilling the core purpose of marriage. In addition, it might surprise many couples who cannot have children (or choose not to do so) that the validity of their marriage rests on its "orientation" toward procreation.