In other words, organic bodily unity is achieved when a man and a woman coordinate to perform an act of the kind that causes conception — a generative act. If it is a free and loving expression of spouses’ permanent and exclusive commitment, a generative act is also marital. Because interpersonal unions are valuable in themselves, and not merely as means to other ends, a husband and wife’s loving bodily union in coitus and the special kind of relationship to which it is integral are valuable whether or not conception results and even when conception is not sought. But two men or two women cannot achieve organic bodily union since there is no bodily good or function toward which their bodies can coordinate, reproduction being the only candidate. This is a clear sense in which their union cannot be marital, if marital means comprehensive and comprehensive means, among other things, bodily. This also explains why our law has historically treated coital consummation, not childbirth, as completing a marriage. In reply, Steorts objects that not all coital acts are of the generative type. While “a millennium or two ago . . . every instance of coitus seemed to be of the same kind,” today we see “physiological differences between fertile and infertile couples” that belie this. But such condescension toward a benighted past is, besides tiresome, misplaced. Of course the ancients knew that there were physiological causes of sterility (e.g., in the elderly, and in all couples most of the time). And yet thinkers like Plato, Aristotle, and Plutarch either took for granted or explicitly affirmed that even sterile coital acts — precisely because of their unitive nature — could be marital.
To see why these remain generative acts, consider digestion, the individual body’s process of nourishment. Different parts of that process — salivation, chewing, swallowing, stomach action, intestinal absorption of nutrients — are each in their own way oriented to the broader goal of nourishing the organism. But our salivation, chewing, swallowing, and stomach action remain oriented to that goal (and remain digestive acts) even if on some occasion our intestines do not or cannot finally absorb nutrients, and even if we know so before we eat.
Similarly, the behavioral parts of the process of reproduction do not lose their dynamism toward reproduction if non-behavioral factors in the process — for example, low sperm count or ovarian problems — prevent conception from occurring, even if the spouses expect this beforehand. As I have argued, bodies coordinating toward a single biological function for which each alone is not sufficient are rightly said to form an organic union. Thus, a man’s and a woman’s bodies can coordinate toward the single biological good of reproduction — and so be united much as organs coordinating toward the single biological good of an individual’s life are — even where physiological factors ultimately prevent conception. Infertile couples can carry out the same (generative) kind of behavior, for the same reason: to consummate or renew — physically seal or embody — their multi-level marital union. Inasmuch as it completes this valuable comprehensive interpersonal union, the marital act is itself valuable. But two men’s or two women’s bodies cannot coordinate toward a single biological good — or organically unite, or physically seal a multi-level personal union — in any sense at all.
BODILY UNION: ESSENTIAL FOR COMPREHENSIVE UNION
Steorts’s thinly veiled contempt for these conclusions — and, implicitly, for the body as part of the person — is exposed when he sneers at the idea that “the value of a relationship between two persons in love [would] depen[d] on the structure of their genitals.” He might as well ridicule the idea that Juliet’s attraction to Romeo would depend “on the structure of Romeo’s genitals,” or for that matter that the moral rights of the comatose would depend on “the structure of their genes,” which code for personhood. Comprehensive interpersonal union requires not what Steorts calls the “experience” of bodily unity (certain pleasures, thoughts, sensations) but its achievement, in coitus. Because our bodies are parts of our persons, “merely bodily” differences can suffuse our whole being and ground moral differences.