They are good representatives of the opposing sides. Corvino is a professor of philosophy at Wayne State University who for many years has been a leading public speaker and writer offering a philosophic defense of the moral dignity of homosexuality. Gallagher is the cofounder of the National Organization for Marriage, which has been the preeminent organization in the United States fighting to preserve marriage exclusively as the union of one husband and one wife jointly caring for their children.
Some of us might think that this debate has been settled in recent years in favor of same-sex marriage by the decision in Obergefell in 2015 and by other legal decisions around the world legalizing gay marriage. On the contrary, now that same-sex marriage is legal in many countries, for the first time in human history, we will see the consequences of this momentous change in marriage and family law, which will provoke a continuing debate over whether this was a good decision or not.
A good debate requires both agreement and disagreement. If the debaters cannot agree on anything, it's impossible for them to talk to one another. But if they agree about almost everything, then there's no debate. The debate between Corvino and Gallagher is a good one, because there's enough agreement and disagreement for them to have a contentious but fruitful conversation.
They agree about the importance of marriage, and so they both reject the arguments of those who think abolishing the institution of marriage would be an improvement in human life. But they disagree about the nature of marriage itself. I stress the word nature here, because they agree that marriage is rooted in human nature--in certain fundamental natural human desires that are universal to all human societies. But they disagree in how they understand those natural ends of marriage. Therefore, this is a debate over the natural law of marriage.
According to Thomas Aquinas, the natural law of marriage points human beings to two natural ends. The primary end of marriage is to secure parental care of children. The secondary end of marriage is the conjugal fidelity of husband and wife. Corvino and Gallagher agree with this understanding of the nature of marriage; but while Corvino believes that this is compatible with extending the idea of marriage to include same-sex marriage, Gallagher denies this, because she believes that this natural law of marriage means that same-sex marriage is not real marriage. To say that two men or two women can be married and achieve these two natural ends of marriage--conjugal fidelity and parental care--is a lie.
Children are most likely to flourish, Gallagher argues, when they are reared by their biological father and biological mother in a stable and low-conflict household, where the father and mother are in a life-long marriage that is sexually exclusive, so that it is never disrupted by adultery or divorce. This is based in the biological reality that the sexual intercourse of a man and a women produces babies, that those babies naturally long for both a mother and a father to care for them, and that while a heterosexual couple in a life-long monogamous marriage can provide this, a gay male couple or a lesbian couple cannot. In a gay or lesbian household with children, the children cannot have a biological connection to both parents, and so the children will always be motherless, fatherless, or both. Moreover, homosexuals--and especially gay men--have a strong propensity to promiscuity that makes it hard for them to sustain stable married households, and most homosexuals have no interest in parenting children. Consequently, legalizing same-sex marriage will harm the children who come under the care of gay or lesbian parents.
This will also weaken heterosexual marriage by teaching people that marriage is more about satisfying the personal desires of adults than about the needs of children, which will promote adultery, divorce, promiscuity, step-parenting, single-parenting, and infertility. This will be bad for both children and adults, because it will frustrate the natural human longings for conjugal fidelity and parental care of children.
Remarkably, Corvino agrees with Gallagher on some of these points. He agrees that securing the parental care of children is one of the primary functions of marriage. He also agrees that children, on average, do best when they are reared by their own married biological parents. And thus he agrees that gay or lesbian parenting is not ideal for children, on average. He also agrees that many homosexuals--particularly, gay men--are so promiscuous that they have little interest in monogamous marriage; and of those who do want to be married, most do not want to care for children.
And yet, even if one agrees with all of this, he argues, it does not follow from this that therefore same-sex marriage is not real marriage as rooted in human nature. First, one should see that although parental care is one of the primary functions of marriage, it is not the only one. What Aquinas identifies as conjugal fidelity is what Corvino calls the "mutual-lifelong-caregiving function" of marriage:
"Marriage promotes mutual lifelong caregiving in a way that no other institution does, a task that is important for gay and straight citizens alike. Put simply, it builds family. In achieving this aim, marriage also accomplishes various related aims: it settles the young, assisting their transition into adulthood; it provides a safe harbor for sexual intimacy; and it creates a stable environment for any children who might arrive or already be present" (20).But while Gallagher sometimes suggests that a marriage without parenting is not real marriage, Corvino insists that mutual lifelong caregiving can stand by itself as the natural function of a marriage, even without children. So a heterosexual couple who marry for the sake of conjugal bonding have a real marriage, even when they are unable or unwilling to have children. And since the same is true for a same-sex couple, there is no reason not to recognize a same-sex marriage without children as a real marriage.
Gallagher and other opponents of same-sex marriage like Robert George have tried to argue that only heterosexual marriages are real marriages because they are oriented to reproduction, which is the natural end of marriage. The biological complementarity of a man and a woman as having bodies that can be joined in coitus to produce a baby is the natural ground for marriage as directed to reproduction. Gay male couples and lesbian couples lack this biological complementarity for reproduction, and thus they lack the natural ground for marriage.
Proponents of gay marriage like Corvino have objected that since many married heterosexual couples do not have children, this shows that parental care is not essential for a marriage. Gallagher and George have responded that even when married heterosexual couples do not have children, their sexual intercourse is still "of a reproductive type." The thought seems to be that the heterosexual insertion of a penis into a vagina is somehow naturally "oriented" to producing babies, even when sterility or contraception prevents this from happening.
But, then, Corvino suggests, it's hard to see how a married couple are "oriented" to reproduction when they intentionally do whatever is necessary to avoid it. Moreover, we can even imagine a man who is a paraplegic--paralyzed from the waist down--who might marry a woman, and this would be a real marriage although sexual intercourse is impossible.
If heterosexual couples can be truly married, because they are committed to lifelong mutual caregiving, even though they will never have children, then, Corvino claims, homosexuals can be truly married when they are similarly committed to such mutual caregiving.
Even Gallagher sometimes contradicts herself by conceding that parental care of children is not the only natural function of marriage. As Corvino points out, this is clear in a book that she coauthored with Linda Waite--The Case for Marriage: Why Married People are Happier, Healthier, and Better Off Financially (Doubleday, 2000). They say that one of the "myths" that they want to refute is "Marriage is mostly about children; if you don't have kids, it does not matter whether you cohabit or marry or stay single" (4). Against this myth, they point to evidence "documenting the powerful effect getting married and staying married has on the well-being of adults. . . . For some people, marriage can literally make the difference between life and death." If marriage is good for the well-being of committed heterosexual couples, even without children, why isn't it equally good for the well-being of committed homosexual couples without children? And if so, that means that conjugal bonding is one of the primary functions of marriage--whether heterosexual or homosexual--that stands independently of other functions such as parenting.
Nevertheless, some gay and lesbian couples do want to become parents, and they seek legal marriage as a way of supporting the stability of their household as the best environment for raising children. It is true, as Gallagher indicates, that the children of a homosexual couple cannot have a biological connection to both parents, and with same-sex parents, the children cannot have both a father and a mother. But it is possible for the children to have a biological connection to one of the parents, although most commonly same-sex couples will bring children into the family by adoption. And as long as it is true, that adoptive homosexual parents are on average as good for children as adoptive heterosexual parents, then legalizing same-sex married parenting poses no special harm to children.
As already indicated, Corvino concedes that the ideal environment on average for raising children is a lifelong heterosexual marriage of mother and father jointing caring for the children. Corvino says that he is grateful that he was raised in this environment, and his parents are still married and still tied to their children.
But in defense of same-sex marriage and parenting, Corvino points out that same-sex couples will never kidnap any children from any heterosexual couples who want to keep their children. Homosexual parents will either produce children through artificial insemination, or they will adopt them. And it is surely better for the children to be brought into existence than not. And it is better for the children in foster care to be adopted.
Against this, Gallagher insists that children have a natural longing for the care of both a mother and a father, that because of the sexual differences between men and women, maternal caregiving is never the same as paternal caregiving, and so a mother can never be a father, and vice versa; and a child ideally should have the care of both the biological mother and the biological father. Corvino agrees that this is the ideal. But he suggests that we all recognize that what is ideal on average is not always attainable, and so we look for parenting arrangements that are good enough on average for children.
So, for instance, Gallagher recognizes that the word "mother" has both a natural meaning and a legal meaning. The natural mother is "the person who bears the child with her body." But if the natural mother cannot or will not perform the maternal function, then "we give a motherless child a mother through the legal process" of adoption (103). This is what Aquinas says when he explains the adoption of children as "art imitating nature," so that the adoptive parent becomes a "similitude" or "likeness" of the natural parent.
This same reasoning justifies the adoption of children by same-sex couples, because their adoptive parenting imitates natural parenting. Even if natural parenting by both biological mothers and biological fathers is best on average for children, adoption is best for children when this ideal is not achievable.
So what we see here, I suggest, is that the natural law of marriage really does point to at least two natural functions of marriage--conjugal bonding and parental care--that can be achieved either by heterosexual marriage or homosexual marriage. Depending upon their natural temperament, heterosexual individuals should marry into an opposite-sex marriage in order to satisfy their natural desires for mutual caregiving or parental care or both, although some by natural temperament will be better off not marrying.
Similarly, by natural temperament, many homosexual individuals will want to marry into a same-sex marriage in order to satisfy their natural desires for mutual caregiving or parental care or both, although many will not want to marry.
Corvino agrees that gay men have the same propensity to sexual promiscuity and less attachment to children as do heterosexual men, except that gay promiscuity is not constrained by women's greater desire for monogamous fidelity and caring for children. At the same time, lesbian women are like heterosexual women in their greater propensity to monogamous bonding and child care. Consequently, same-sex marriages with children will be more common among lesbians than among gay men.
We can predict, then, with the legalization of gay marriage, that most homosexuals will have no interest in monogamous marriage, that most same-sex marriages will have no children, and that most of the monogamous same-sex marriages with children will be based on lesbian couples.
If this prediction comes true, there is nothing here that threatens heterosexual marriage or harms children, and therefore no reason to oppose the legalization of same-sex marriage. If marriage really is natural because it satisfies natural human desires for conjugal bonding and parental care that cannot be satisfied well in any other way, and if this is as true for same-sex marriage as it is for heterosexual marriage, then we can expect that the social norms supporting marriage--such as monogamous sexual exclusivity and parental devotion to children--will endure even while many individuals will violate those norms.