The Possibility of Dialogue
    I have suggested that, despite their other differences, certain opponents and supporters of same-sex marriage agree that norms embodied in cultural practices must refer to something beyond human experience if they are to have binding force. If they cannot, differences become simply a matter of taste, not morality.
    Must we accept this set of choices? Must cultural norms be grounded in an objective moral order in order to have any ethical claim on us? I suggest that the answer is no and that the debate over same-sex marriage in fact offers an example of how human practices and experience can serve as the basis for moral commitments.
    Social institutions such as marriage and the family are not simply arbitrary conventions. To be sure, they possess features that are the product of historical contingency and cultural variation. Nonetheless, social practices and the norms that are associated with them persist because they tend to satisfy some of the basic requirements for human flourishing, such as sustenance, the need for emotional connection with others, a sense of human dignity, the need for meaning, the care of children and other vulnerable members of society, perpetuation of the human species, coping with the frailties of age, and confronting the inevitability of death.
    Those practices that speak to these needs become infused with moral significance because they help us function as distinct human beings rather than as generic animals. We assess the morality of a given practice by asking: What kind of lives does this practice enable people to lead? Are they lives that embody our best notions of human dignity and responsibility? Do they contain an adequate measure of the features we regard as essential to living a good life? The answers to these questions are never transparent and are always open to debate, discussion, and sometimes fierce conflict. No social form is automatically exempt from challenge as new conditions arise. Nonetheless, those practices that persist are entitled at least to prima facie respect. They have withstood the process of challenge and justification because they seem to respond to important human concerns and needs. As such, they are the products of accumulated historical experience from which we should learn, not arbitrary conventions whose existence reflects pure historical accident. As Goethe put it, "He who cannot draw on three thousand years is living from hand to mouth."
    At the same time, we need not approve of every social development that emerges simply because it persists. Slavery, sexism, and racial discrimination have flourished for centuries, but their pernicious effect on human beings rightly leads us to condemn them. Unwed teenage pregnancy has become more widespread, but that alone does not mean that we must resign ourselves to its inevitability. Asking what kinds of lives this practice makes available for both parents and children can lead us to respond in different ways. We must inevitably make judgments about whether accommodation or resistance is the better course.
The fact that marriage has persisted for centuries suggests that this social institution should be respected as one that meets enduring human needs. At the same time, the emergence of gay men and lesbians as self-conscious groups whose members desire to formalize their romantic commitments has generated a debate about just what those needs are. The contradictions and tensions of everyday experience thus have created an occasion for clarifying the meaning of marriage in the face of new historical circumstances. How might a dialogue on this subject proceed? I cannot elaborate fully here on the form that it might take, not least because it is impossible to predict the myriad paths down which any conversation might go. It may be useful, however, at least to sketch the broad outlines of such a debate.

The Case of Children
    We might begin with the role of marriage in providing a stable environment in which to create and raise children. Fulfilling this responsibility is crucial both for the welfare of individual children and for society. Same-sex partners obviously are distinguished from heterosexual ones by the fact that they cannot produce biological offspring. Even Andrew Sullivan, a supporter of same-sex marriage, has acknowledged that married homosexual couples may well be less likely to engage in childrearing than are heterosexual couples. Opponents may voice concern that permitting same-sex unions would de-emphasize the role of procreation in marriage, with a corresponding increase in emphasis on individual emotional satisfaction as the chief function of the institution. This shift in cultural meaning could harm children by subordinating their welfare to that of their parents, as well as eventually threaten the ability of society to reproduce itself. From this perspective, marriage is a social institution that uses the fact of sexual difference to nurture an ethic of altruism and selflessness that redounds to the benefit of society and its most vulnerable members.
    Supporters of same-sex marriage might respond in two ways. First, they might accept the centrality of procreation and childrearing to marriage, but contend that same-sex unions do not threaten the performance of that function. Biological procreation is not the only way that adults may assume the responsibilities of parenthood in modern society. Many homosexuals have already committed themselves to the care of children through adoption or nontraditional means of procreation. Studies suggest that children raised in such households are no more at risk than those raised by heterosexual couples. Indeed, the argument might go, gay men and lesbian parents typically make a much more deliberate decision to become parents than heterosexual couples, for whom accidental procreation is possible. This claim requires us to consider the relative significance of biology and choice. Does the creation of life through heterosexual intercourse provide a better guarantee of parental devotion than parent- child relationships formed in other ways? Or should we regard nontraditional avenues for becoming a parent as equally valuable because they always involve a deliberate commitment? One path of dialogue thus might accept the proposition that the creation and care of children is a crucial element of marriage, but require us to reflect on what features of marriage are necessary for fulfillment of that social responsibility.
    Homosexuals alternatively might contest the claim that procreation is central to contemporary marriage. Childless heterosexual couples are increasingly common. High divorce rates create a substantial number of nonmarital parent households. The number of out-of- wedlock births is sharply up. Finally, some percentage of heterosexual couples are incapable of procreation because of either voluntary or involuntary sterility. Society nonetheless does not deny them the status of marriage despite this ostensible defect. Childless same-sex couples thus would hardly represent an anomaly in a culture that already has begun to separate marriage and procreation.
    Furthermore, the absence of biological difference in same-sex couples can change marriage for the better by undermining the virtually automatic division of labor in which women are deemed primarily responsible for the care of children. Same-sex parenthood within marriage, the argument might go, thus carries the promise of freeing us from rigid assumptions about childrearing that may have deleterious effects for both children and the genuine equality of marital partners.
    In response, opponents may argue that some studies of divorced and single-parent households raise concern that nontraditional caregiving arrangements are less successful than those involving married biological parents. We therefore should seek to reduce, rather than expand, the number of such households. Furthermore, some may assert that efforts to change the roles of men and women in childrearing reflect the pursuit of an abstract ideal that ignores evidence of the distinctive nurturance that women tend to provide. Critics thus may claim that the potential for same-sex marriage to transform our understanding of both marriage and parenthood is precisely why we should not legally bless such unions. However this debate may be resolved, the important point is that it is through such dialogue and reflection that a culture gains a deeper appreciation of the values that constitute and sustain its primary institutions.

Promoting Commitment and Sexual Restraint
    A second arguably important function of marriage is to promote long-term emotional commitment and restrain sexual license. Supporters of same-sex marriage such as Eskridge and Rauch maintain that a particularly significant aspect of this function is marriage's role in curbing male promiscuity. Opponents may in turn argue that even gay and lesbian advocates acknowledge patterns of greater sexual license in the homosexual community, especially by men; the danger is that same-sex partners may continue to exhibit this tendency if they choose to marry, thus transforming our expectations of marriage for the worse. Such a prospect is even more probable if homosexual couples are less likely to have children, because they will lack the constraint on their impulses that parental obligation provides. It is also particularly important, opponents might claim, to encourage men to enter into relationships with women because of the civilizing force of femininity.
    Proponents of same-sex marriage may respond in two ways. First, they could accept the claim that marriage should involve emotional commitment and sexual fidelity, but argue that same-sex relationships are as capable of exhibiting those qualities as heterosexual ones. Any patterns of promiscuity that may exist reflect not inherent traits of homosexual relationships, but the unfortunate effects of an absence of social reinforcement for commitment by gay and lesbian couples. This makes it all the more short-sighted for a society that values loyalty and sexual restraint to deny marriage to same-sex partners.
    Furthermore, there are numerous examples of couples who have surmounted the social obstacles and established long-term, marriage-like relationships. Many partners have displayed extraordinary devotion in the care of loved ones with AIDS. Most of these partners have been men taking care of other men, thus belying the notion that gay males are incapable of meeting the demands of deep emotional commitment. Such experience arguably presents a challenge to the conventional assumption that women have a superior capacity for nurturance that makes them crucial to the marriage relationship. In light of this challenge, creating social pressure on gay men to enter heterosexual marriages is a misguided policy that hardly advances the goal of family stability. Given a current divorce rate of close to 50 percent, the argument might go, heterosexuals are not inherently better than homosexuals at sustaining long-term relationships. A genuine dialogue thus can force us to consider to what extent the union of masculine and feminine is crucial to the commitment that we regard as an integral feature of marriage.
    Supporters of same-sex marriage alternatively might question whether marriage should involve an expectation of sexual fidelity or long-term commitment. Are such expectations realistic in an age in which marriages may last for 50 or more years? Has modern culture already moved toward separating sexual gratification from emotional involvement among heterosexuals? Those who challenge the current marital ideal may contend that it is a relatively recent historical phenomenon rather than a timeless element of marriage. The ideal is wrong-headed, the argument might go, because it places a profound burden of unrealistic romantic expectations on marriage. This burden actually leads to a higher divorce rate, as individuals pursue the chimera of unalloyed physical, emotional, and spiritual union in a succession of marriages that inevitably fall short of the ideal. The notion of exclusive long- term commitment thus represents a misguided unwillingness to accommodate natural human frailty and imperfection.
    Opponents may counter that the historical contingency of the ideal of marital commitment does not deprive it of normative force. Any social practice has a large element of contingency, but the tenacious persistence of this one over a period of centuries testifies to its responsiveness to deeply rooted concerns. That the ideal is not universally attained hardly undermines its significance; it is in the nature of an ideal that it serves as a call to master impulses that may have a more immediate and direct appeal. In particular, opponents might claim, an ethic of sexual fidelity is important because sexuality is an unruly and powerful force that has a distinctive potential to disrupt human relationships. Those who suggest that we can give such a drive free rein without endangering the stability of emotional connections exhibit not wisdom but hubris. Again, however we resolve this debate, the discussion itself can be a valuable opportunity to think deeply about the significance of the marriage vow.
    Some of the arguments in the dialogue I have sketched may be examined empirically. Others may depend on their resonance with more subtle chords of assent or dissent. Furthermore, any resolution necessarily will be tentative, for as social conditions change, so too must social practices. We cannot specify with precision the course of this debate. Human speech perpetually carries the potential to evoke new meanings and new self-understandings. Our very understanding of what marriage is will be shaped by our discussion of it.
    One thing is clear, however: the dialogue cannot be sustained indeed, cannot be begun by invoking either biology or universal rights as a trump card that precludes further discussion. Clearly we must take certain biological facts into account. But we have wide latitude in determining just what significance to place on those facts skin color, reproductive capacity, and congenital physical conditions represent but a few of the facts of nature toward which our attitudes have evolved over time. Similarly, we have come to regard some aspects of experience as entitled to individual control regardless of popular sentiment. We call these rights. These aren't revealed to us, however, through close attention to the structure of the universe. Rather, they reflect the evolution of our culture's sense that effective human agency requires that some decisions be left to individuals. This is not the demarcation of an arena of life that is free of moral assessment; drawing the boundary itself reflects an act of moral judgment.

A Slippery Slope?
    We must engage in the debate that I have suggested equipped simply with our understandings of human experience, values, and purposes, however widely those understandings may diverge. If this leads us to accept same-sex marriage, does it mean that we have no persuasive way of defending prohibitions on marriage between blood relatives or among more than two people?
    Hardly. Prohibitions on incest reflect concern for the important values of protecting children's vulnerability, fostering trust among family members, and encouraging nonsexual relationships among persons who feel a sense of obligation toward one another not based solely on individual choice. While specific proscriptions vary, all cultures have some form of prohibition based on family relationship. Similarly, polygamy has never been a widespread practice. It has tended to meet with consistent disapproval in all Western societies, where for quite some time there has been a strong sense that marriage involves the commitment of one individual to another. There is no substantial group of persons who have turned to polygamous arrangements as a way of meeting important human needs in the face of modern historical circumstances. Thus, we need have little concern that prohibiting polygamy would deprive some individuals of the opportunity to engage in a social practice essential to human flourishing as we currently understand it. We therefore can distinguish same-sex marriage from incest or polygamy by reference to the kinds of lives that they make possible and the values that they serve.
    Even if these arguments are persuasive, however, they do not cut off discussion once and for all. It is at least conceivable, for instance, that human circumstances a century from now may be such that polygamy meets important needs and serves significant values. While this sense of contingency may create a sense of anxiety, it also offers us an opportunity: to take responsibility for shaping and reshaping our social forms to preserve the possibility of human dignity and meaning in a world of dynamic and often random events.
    The debate over same-sex marriage is but one opportunity for us to use public dialogue to constitute ourselves as a moral community. Doing so is inescapably a collective enterprise in making meaning, in which we educate each other about the diverse forms of human experience. That process requires that we treat with respect those who invoke what they regard as objective authority for their positions. It also, however, demands that those who hold these views attend to the arguments of those who do not accept such authority. In a modern world marked by heightened self-consciousness of human choice, the invocation of neither biology nor universal rights can relieve us from the communal task of deliberating about the meaning of marriage.

Milton C. Regan, Jr. is a professor of law at Georgetown University Law Center and author of Alone Together: Law and the Meanings of Marriage (forthcoming) and Family Law and the Pursuit of Intimacy.
    Reprinted with permission from The Responsive Community (ISSN 1053-0754), published quarterly by the Center for Policy Research, Inc., The George Washington University, Washington DC 20052, USA. Tel: (800) 245-7460. http://www.gwu.edu/~ccps/rcq/index.html