I can't comment on the law, but I would argue that one does not have a moral obligation to have sex with one's partner in marriage. In fact, I can easily think of cases in which one has an obligation not to have sex with one's partner, e.g., if one's partner doesn't want to have sex. Another case is one in which one's partner's health is such that one would cause harm to him/her by having sex.

You might be wondering, though, about cases in which one partner wants sex and the other doesn't. Does the undesiring partner have an obligation to have sex with the desiring partner? I would argue that there isn't such an obligation or anything even close. Certainly there is no obligation to have sex with someone you don't desire outside of marriage, so the source of the obligation must be marriage. And I have never heard a marriage vow that includes: "and I promise to have sex with you even if I don't want to." It may be that assumptions around the institution of marriage make it plausible that there is an implicit promise to have sex, so it may be disappointing (to say the least) if one finds oneself in a marriage with someone who doesn't want to have sex. But this doesn't entail a right to sex.

I would argue that, in fact, one has an inalienable right to refuse sex, and this right stems from an inalienable right to one's body. If there are any rights at all (which I'm not going to argue for here), then a right to one's body seems to be one of the most basic. I cannot make a binding promise to you that I will give you my arm or leg, or even my heart; I cannot make a binding promise to become your slave. Likewise, even if there seems to be an implicit promise to have sex in the institution of marriage, the promise isn't binding. Moreover, one could argue that it would be a violation of one's duty to oneself to engage in sex that one didn't want under pressure from one's partner. (Several different grounds for inalienable rights have been proposed, one of them being in the obligations one has, first and foremost, to oneself. Also, on this theme, Robin West has a useful article entitlted "The Harms of Consensual Sex" you might consider looking at.) Historically, however, the right to refuse sex was not granted to a married woman (legally, rape could not occur within marriage). So there have been views according to which even if one has an inalienable right to one's body, this does not entail the right to refuse sex within marriage. I would suggest, however, that such views probably rest upon faulty conceptions of sex and/or marriage.

I'm back, after only three days of teaching, grading, and occasionally goofing off. Here are a few thoughts about the issue and Professor Haslanger's reply to the question.

(1) Professor Haslanger writes, “Certainly there is no obligation to have sex with someone you don't desire outside of marriage, so the source of the obligation must be marriage.” This claim nearly begs the question. What holds for marriage might hold also for longstanding relationships, or for couples who live together without a formal marriage, and vice versa. So the “certainly” is suspicious. Martha Nussbaum, for one, in raising a different question (one about how to attenuate noxious sexual objectification), sees no relevant difference between sexual relations in a longstanding relationship without formal marriage and sexual relations in one with formal marriage. (“Objectification,” in my Philosophy of Sex, 4^th edition, pp. 381-419.) Indeed, Haslanger’s “rights” answer to the question applies equally to marriage, nonmarital relationships, even causal encounters or meetings. “Rights to one’s body” are not limited, if they are as important as she thinks they are, by such accidental, external conditions.

(2) Professor Haslanger’s claim, “I can easily think of cases in which one has an obligation not to have sex with one's partner, e.g., if one's partner doesn't want to have sex,” is too strong. It might well depend on why one’s partner does not want to have sex. Haslanger thinks that “rights to one’s body” give the correct and only possible answer to the question, that such rights are the only morally relevant consideration. But I’d argue that there is more to this moral story than “rights” and correlative “obligations” or duties (just as there is more going on in many, if not all, moral stories). Other notions that are relevant are justice, the virtues (e.g., benevolence, honesty, integrity), and even mere prudence. All these factors may play a role in our decisions (and our moral judgments about) whether to engage in sex with our partner when we are not especially in the mood to do so, when we have no desire to do so, when we would rather be reading a book or watching television. These are possible if not frequent reasons for not wanting to have sex (with one’s partner), but they are not as significant as being sick, or being exhausted and needing to sleep, or having a splitting migraine headache. This is why Professor Haslanger’s answer to the question, with its monolithic emphasis on inalienable rights, strikes me as insensitive to the complexities and subtleties of human interactions, and reminds me (curiously?) of Robin Morgan’s definition of rape: “Rape exists any time sexual intercourse occurs when it has not been initiated by the woman, out of her own genuine affection and desire. . . . How many millions of times have women had sex ‘willingly’ with men they didn't want to have sex with? . . . How many times have women wished just to sleep instead or read or watch the Late Show? . . . Most of the decently married bedrooms across America are settings for nightly rape” (Going Too Far, 165–66). Again we need to address moral differences between various reasons why one might not want to have sex with one’s partner. (An analogy: from the inalienable “right to one’s body,” some philosophers, including Judith Jarvis Thomson, derive the moral permissibility of abortion. But even Thomson admits that some reasons for a woman’s having an abortion, cashing in her right to do so, are “indecent,” implying that talk of “rights” is not the whole moral story.)

(3) Professor Haslanger says, “I have never heard a marriage vow that includes: ‘and I promise to have sex with you even if I don't want to’." But she forgets the long tradition in Christianity, especially Roman Catholicism, according to which one of the purposes of (sex in) marriage is to serve as a “remedy against sin,” from which the “conjugal debt” is derived (the other purposes are the procreative and the unitive; see Pope Paul VI’s 1968 encyclical “Humanae vitae”). The “remedy against sin” and the “conjugal debt” in Christianity began with St. Paul, in 1 Cor. 7:1-9; they can be found (if only between the lines) in the Bishop who admired Paul, St. Augustine, in his account of the goods of marriage (De bono conjugali); and they are notions well-developed by medievalists, especially St. Thomas Aquinas in Summa theologiae, Supplement, 64.1ff. It can also be found in ancient Hebrew texts; Talmudic scholars seriously asked how often spouses should fulfill the debt, i.e., the duty to engage in sex with one’s spouse. The idea is that having satisfying sex in marriage is the “remedy” for inclinations to engage in promiscuous fornication, which is a spiritual disaster. Each spouse owes sexual activity to the other spouse precisely for this reason, to help the spouse overcome tendencies toward sinfulness; a spouse who denies the other spouse sex too often fails to satisfy that spouse’s sexual needs, which frustration increases the tendency to commit fornication. Paul allowed exceptions, as any reasonable person would: he explicitly says that if one spouse is engaged in prayer or other spiritual activity (not watching “The Late Show”), at those times the debt need not be fulfilled; and he implies (see his phrase “due benevolence”) that illness and similar factors provide reasons not to fulfill the debt or ask that it be fulfilled. As far as I know, these three purposes of marriage, or of sex in marriage, the procreative, the unitive, and the remedial, are central to the current Catholic conception of marriage, even if they are not stated explicitly in the marriage vow (and even if they are not stated explicitly in the Catechism). Haslanger’s reply seems to be that “such views probably rest upon faulty conceptions of sex and/or marriage.” Faulty? How so? Because they come from a religious tradition that has been rejected by much of contemporary American culture? That’s not the most powerful argument I’ve come across against Christian sexual ethics.

(4) On how justice, perhaps distributive justice (rather than “rights”), figures into this moral issue has been discussed in interesting ways by Alan Wertheimer (Consent to Sexual Relations, 275-76; “Consent and Sexual Relations,” in my Philosophy of Sex, 5^th edition, esp. pp. 309-13) and by Robin West (not in “Harms of Consensual Sex” [in Philosophy of Sex, 5^th edition, pp. 317-24], but in her “A Comment on Consent, Sex and Rape,” Legal Theory 2:3 [1996], 233-51). My own two cents can be found in “Orgasmic Justice,” pp. 53-58 of my Sexual Investigations. Of course, “wants” and “not-wants” will be taken into account by distributive justice, but they do not have the overwhelming power attributed to them by Haslanger. A distributive justice answer to the question might reasonably conclude that “wants” and “not-wants” should be satisfied 50/50. Or construct your own formula, one that is sensitive to the intensity of the partners' "wants" and "not-wants."

(5) Finally, the thoughts of my philosophy of sex students, who occasionally have a better gut-reaction grasp on such things than academic philosophers. They commonly answer the question in a variety of ways, including these two. (A) if X loves Y, or even if X merely cares about Y’s psychological and physical well-being (the virtue of benevolence), then X will agree to have sex with Y even if X prefers to watch the Late Show. The inalienable right to one’s body can, after all, be alienated, without moral calamity. (B) Without knowing a word of Paul, they recognize that a spouse (male or female) who insists on an inalienable right to say “no” runs the risk of alienating the affections of the other spouse, of driving the other spouse to other ways of achieving sexual satisfaction (maybe cybersex with anonymous chatters), and of endangering the viability of the relationship itself. Maybe a spouse doesn’t want to have sex right here and now, but he or she also wants to maintain the relationship (and not necessarily or always for economic reasons), and the inalienable right to say “no” to sex gives way, on balance, to the desire to maintain the relationship. That spouse values human connection more than abstract rights.