This fertilization of a woman's egg by a man's sperm might be seen as showing why the evolution of human sexuality has made the female human nature and the male human nature so different. But then we must wonder whether gay men and lesbians show this same male/female difference, or whether homosexuality is itself a distinct human nature. And if so, does this mean that homosexual marriages must differ by nature from heterosexual marriages?
The evolution of mammalian reproduction through male insemination of a female and the internal fertilization of the female's egg inside her body means that the minimum parental investment of a mother is usually much greater than the minimum parental investment of a father, which creates a difference on average in the natural mating desires of males and females. Throughout the evolutionary history of our human ancestors, women had to invest in each offspring at least nine months of pregnancy and many months if not years of nursing and caring for the infant, while men could potentially impregnate many women without any additional investment in the developing fetus or the newborn child. Men can increase the number of their offspring by promiscuous mating, but women cannot.
If Robert Trivers (1972) is right in his Darwinian theory of mating strategies as determined by parental investment, we should expect that women will typically be more selective than men in choosing mates, and women will typically desire mates with resources that can support her and her children.
David Buss (2016) and others have surveyed the mating preferences of people around the world, and they have found that men prefer to mate with women who are young and physically attractive, while women prefer to mate with men who have economic resources and high social status. Since the reproductive success of a man depends predominantly on the fertility of his mate, Darwinian theory predicts that the visual cues to fertility in nubile women--such as youth, smooth skin, luscious hair, regular facial features, and good body tone--are sexually attractive to men around the world. Since the reproductive success of a woman depends predominantly on the ability and willingness of her mate to invest resources in her and her children, we can predict that the social cues to such resources in men--such as wealth, status, older age, and ambition--are sexually attractive to women around the world.
These natural differences in the mating preferences of men and women create conflicts of interests--the battle of the sexes. Lifelong monogamous marriage is an attempt to strike a truce in that battle by finding a mutually beneficial compromise in which neither sex exploits the other. A monogamous marriage benefits the wife because her husband agrees to invest emotionally and materially in her and in any children they produce without diverting his resources to other sexually attractive women. A monogamous marriage benefits the husband because his wife agrees to give him faithful attachment and exclusive sexual access to her, so that he need not suffer from sexual jealousy, and he can be sure that his parental investment is going to his own children and not to children sired by another man. In this way, her reproductive success becomes his, and vice versa. For this to work, the man must sacrifice his natural male desire for sexual variety to satisfy his natural desires for conjugal bonding and parental care. Turning away from the reproductive strategy of maximizing the quantity of his offspring through promiscuous mating, he must follow the reproductive strategy of maximizing the quality of those few offspring who benefit from his intensive paternal care.
If this Darwinian account of the natural sex differences between men and women, and of how heterosexual marriage forces a compromise of these differences, is correct, then we should see confirmation for this in the sex lives of homosexuals. In The Evolution of Human Sexuality (1979), Donald Symons observed:
"There is no reason to suppose that homosexuals differ systematically from heterosexuals in any way other than sexual object choice . . . . I have argued that male sexuality and female sexuality are fundamentally different, and that sexual relationships between men and women compromise these differences; if so, the sex lives of homosexual men and women--who need not compromise sexually with members of the opposite sex--should provide dramatic insight into male sexuality and female sexuality in their undiluted states. Homosexuals are the acid test for hypotheses about sex differences in sexuality" (292).
"Homosexual men behave in many ways like heterosexual men, only more so, and lesbians behave like heterosexual women, only more so" (304).Here and throughout his book, Symons assumed that while heterosexual men and women manifested different human natures as shaped by the evolution of different reproductive strategies, homosexual men and women did not show any evolutionarily distinct homosexual nature. But in doing that, he left his readers wondering how homosexuality could have evolved as part of human nature if in fact homosexuality reduces reproductive fitness. He offered no solution to what I have called the Darwinian puzzle of homosexuality (here).
Symons saw evidence that homosexuals show the natural male-female differences in many respects--including sexual arousal by visual stimuli, the promiscuous seeking of sexual variety, and the importance of physical attractiveness for sexual desirability. As one indication of this difference, lesbians have no interest in the female nudity displayed in men's magazines like Playboy. And while the male nudity in a magazine like Playgirl is supposed to appeal to heterosexual women, there is reason to believe that the primary audience for Playgirl is homosexual men.
Like heterosexual men, gay males have a natural propensity for seeking out new sexual partners for one night stands. And for both straight and gay men, purely physical attractiveness is their primary concern. That's why homosexual men are so careful about their looks--with a emphasis on good grooming, nice clothes, and physical fitness--because they are like heterosexual women in that they can seduce men only if they are physically attractive. And looking youthful is paramount, which is why gay men are like heterosexual women in their dread of ageing.
Unlike gay men, Symons argued, lesbians are like heterosexual women in that while the physical attractiveness of potential mates is important, at least as important is social intimacy with their mate. As Symons put it, "among men, sex sometimes results in intimacy; among women, intimacy sometimes results in sex" (301).
Symons suggested: "heterosexual men would be as likely as homosexual men to have sex most often with strangers, to participate in anonymous orgies in public baths, and to stop off in public restrooms for five minutes of fellatio on the way home from work if women were interested in these activities. But women are not interested" (300).
Symons implied that the institution of heterosexual marriage is an unnatural constraint on male desires imposed by women to satisfy female desires. Symons is wrong about this, because despite the conflict between male and female desires, there is a fundamental complementarity in their desires for the stable arrangements of marriage and family life. Even Symons recognized this complementarity in a few passages of his book. "The desire for sexual variety," he wrote, "dooms most human males to a lifetime of unfulfilled longing; when the desire can be satisfied easily, as among many homosexual men, it often frustrates the satisfaction of other desires, such as those for intimacy and security" (228).
If marriage did not satisfy male desires, it would not be a universal practice of all societies. If most men found the institution of marriage ultimately unsatisfactory, they would have abolished it long ago. They have always had the power to do so, because every human society has been ruled by men.
Beginning as early as the 1950s and 1960s in the United States, some homosexuals began arguing for legalizing homosexual marriages as a way of providing social encouragement for homosexual monogamy, although some conceded that monogamous commitment is usually easier for lesbians than for gay men. And yet many in the gay community have scorned the idea of gay marriage as contrary to the liberationist culture of gay life that should challenge the stultifying bourgeois norms of traditional marriage (Frank 2017).
The first governmental legalization of gay marriage occurred in the Netherlands in 2001, which was followed by some other European countries. In the United States, Massachusetts was the first state to legalize gay marriage in 2003 through a decision of the Massachusetts Supreme Court (Goodridge v. Department of Public Health). By the spring of 2015, 37 states allowed gay marriage; and at the end of June of that year, the Supreme Court of the United States declared gay marriage to be a constitutional right in Obergefell v. Hodges. (I have written about Obergefell in June and July of 2015 and March and April of 2019).
So now, for the first time in human history, we are experimenting with legalized same-sex marriage. The experiment will determine its success or failure.
Based on my argument for the Darwinian natural law of gay marriage--that it can satisfy the same natural desires for conjugal bonding and parental care that are satisfied in heterosexual marriage--I can predict at least partial success: some gays (though maybe not most) will marry and sustain long-term monogamous commitments, but this will be more successful among lesbian couples than gay male couples; and many of these same-sex marriages will include parental care of children. The critical question is what proportion of the gay male couples will manage to constrain the gay male propensity to promiscuous infidelity.
Depending on how one looks at it, we already have one case of a gay male couple that has been legally married for 48 years, and some historians consider them to be the first same-sex couple in history to be legally married. On May 18, 1970, Michael McConnell and Jack Baker arrived at the Hennepin County Courthouse in Minneapolis, Minnesota, to apply for a marriage license. Baker was a first-year law student at the University of Minnesota Law School, and he had noticed that the Minnesota statute on marriage licenses did not require that applicants identify their sex. Having learned in law school the principle that "whatever isn't prohibited by law is permitted," he told McConnell that they had the legal right to marry in Minnesota. When they arrived at the courthouse, news reporters and photographers were there, because they had alerted the press. They wanted their filling out an application for a marriage license to be a public statement about the right of gays to marry (McConnell et al. 2016).
Gerald R. Nelson, clerk of district court, Hennepin County, refused to issue the marriage license. A few months later, Baker filed for a writ of mandamus in Hennepin County District Court, which would have required the officials in Hennepin County to carry out their legal duties in issuing the marriage license. Among their legal arguments, they claimed that if Minnesota law was interpreted as denying the right of gays to marry, this would violate the United States Constitution by denying them a fundamental right to privacy guaranteed by the Ninth Amendment and by depriving them of liberty and property without due process and of the equal protection of the law, both guaranteed by the Fourteenth Amendment. In making these arguments, they knew that in the 1970s, a congressional statute said any interpretation of the federal constitution by a state court was entitled to automatic review by the U. S. Supreme Court. So when the district court judge dismissed their case, they appealed to the Minnesota Supreme Court; and when their constitutional arguments were denied by that court in 1971, they were entitled for review by the U. S. Supreme Court. This was the case of Baker v. Nelson.
In the Appellant's Jurisdictional Statement, in 1972, the lawyers for Baker and McConnell defended their constitutional right to marry by indicating that same-sex marriage was similar to heterosexual marriage in promoting the two natural ends of marriage--conjugal bonding and parental care--and thus they implicitly made the same natural law argument for same-sex marriage that would be made by Justice Anthony Kennedy in Obergefell v. Hodges in 2015.
To justify a governmental ban on same-sex marriage as consistent with the "equal protection of the laws" guaranteed by the Fourteenth Amendment, the lawyers argued, the Supreme Court's equal protection doctrine would require "a legitimate government interest which is so compelling that no restrictive means can be found to secure that interest, if there is one, than to proscribe single sex marriages" (p. 15). One possible legitimate interest for marriage law might be to make marriage turn on marriage partners being willing and able to procreate and raise children. But this purpose cannot justify banning same-sex marriage. they explained: "There is nothing in the nature of single sex marriages that precludes procreation and child rearing. Adoption is quite clearly a socially acceptable form of procreation. It already renders procreative many marriages between persons of opposite sexes in which the partners are physically or emotionally unable to conceive their own children. Of late, even single persons have become eligible to be adoptive parents" (pp. 14-15).
Actually, of course, the marriage law in Minnesota and other states validates the marriages of childless heterosexual couples, and thus it recognizes the conjugal bonding of a couple as a natural purpose of marriage that stands independently of parental care as a sufficient ground for marriage. But then to allow marriage for childless heterosexual couples while denying it for childless same sex couples violates the constitutional standard of "equal protection of the laws."
In support of this conclusion, the lawyers for Baker and McConnell cited the Court's recent decision in Reed v. Reed, 92 S. Ct. 251 (1971), which struck down an Idaho statute, which provided that as between persons equally qualified to administer estates, males must be preferred to females, as an unconstitutional violation of the equal protection clause of the Fourteenth Amendment. The lawyers quoted from that decision:
"In applying that clause, this Court has consistently recognized that the Fourteenth amendment does not deny to States the power to treat different classes of persons in different ways. [Citations omitted.] The Equal Protection Clause of that Amendment does, however, deny to States the power to legislate that different treatment be accorded to persons placed by a statute into different classes on the basis of criteria wholly unrelated to the objective of that statute. A classification 'must be reasonable, not arbitrary, and must rest upon some ground of difference having a fair and substantial relation to the object of the legislation, so that all persons similarly circumstanced shall be treated alike.' Royster Guano Co. v. Virginia, 253 U.S. 412, 415 (1920)."Since childless same sex couples are "similarly circumstanced" to childless heterosexual couples, they must be treated alike. They must have an equal right to marry, because they are equal in their need for marriage to secure their natural desire for conjugal bonding: "how better may two people pledge love and devotion to one another than by marriage" (p. 7).
In their Appellee's Motion to Dismiss Appeal and Brief (Baker v. Nelson , no. 71-1027), the lawyers for Hennepin County made six arguments for dismissing the appeal. Their first argument was that this case did not present "a substantial federal question," because the power to regulate marriage was exclusively a power of the states, and therefore beyond the authority of the national government. This turned out to be the decisive argument for the Court, because a law clerk for Justice Harry Blackmun drafted a one-sentence rejection of the appeal that was approved by the Court: "The appeal is dismissed for want of a substantial federal question" (Baker v. Nelson, 409 U.S. 810 ). Years later, the man who had been Blackmun's law clerk in 1972 said "I just didn't think the Court was ready at the time to take on the issue" (Bravin 2015). In subsequent years, this was cited by opponents of same sex marriage as a decisive precedent of the Court allowing states to ban same sex marriage. Overruling this decision in Obergefell v. Hodges in 2015, Justice Anthony Kennedy wrote: "The Court now holds that same-sex couples may exercise the fundamental right to marry. No longer may this liberty be denied to them. Baker v. Nelson must be and now is overruled, and the State laws challenged by Petitioners in these cases are now held invalid to the extent they exclude same-sex couples form civil marriage on the same terms and conditions as opposite-sex couples."
The second argument for dismissing the appeal was that the right to marry was not in fact being withheld from either Baker or McConnell, because each was free to marry as long as they married someone of the opposite sex (p. 5). But this ignored the fact that the Court had rejected a similar argument a few years earlier in Loving v. Virginia (1967), when Virginia's law against interracial marriage was declared an unconstitutional violation of equal protection, which rejected the specious argument of the lawyers for the state of Virginia that blacks and whites had an equal right to marry as along as they married someone of the same race as they. And, indeed, the lawyers for Baker and McConnell stressed the importance of the Loving decision in showing how the equal protection doctrine should uphold the constitutional right not only to interracial marriages but also to same-sex marriages. To refute this reasoning, one would have to show that while interracial marriages do not subvert the natural purposes of marriage, same-sex marriages do.
This points to the third argument for dismissing the appeal--the claim that same-sex marriage would "defeat and destroy" the institution of marriage (p. 6). This claim has been developed by many of the opponents of same-sex marriage--such as Maggie Gallagher and Hadley Arkes. Arkes has said: "It is not marriage that domesticates men; it is women" (1993). Marriage domesticates men when they marry women, not when they marry other men. If Symons is right about the socially destructive natural propensity of men to promiscuity, then heterosexual monogamous marriage is good for men and for social order generally because it forces men to constrain their restless desire for sexual variety by compromising with the demands of women for monogamous permanence and fidelity. If "marriage equality" means that same-sex and opposite-sex unions are treated equally as marriages, then this is based on a lie about human nature--the lie that there is no natural difference between a union of two men or two women and a union of a man and a woman. In fact, few male same-sex couples adhere to the norm of monogamous fidelity because they are free from the constraints of female sexuality. Stretching the definition of marriage to include the same-sex marriage of men will therefore destroy the heterosexual marital norm of monogamous fidelity and permanence (Corvino and Gallagher 2012, 129-149).
But as John Corvino and others have noted, this ignores the fact that lesbian couples do seem to have a strong natural propensity to monogamous stability. If it's good to marry a woman, it must be even better for women to marry other women! Gallagher concedes this when she cites research showing "that whereas monogamy is correlated with relationship satisfaction for heterosexuals and lesbians--that is, having monogamy is associated with being in a happy relationship--for gay men, there's no association between sexual exclusivity and the satisfaction of the relationship" (Corvino and Gallagher 2012, 135).
So should we legalize heterosexual marriages and lesbian marriages, while banning gay male marriages, because legally recognizing the marriage of men would endorse male promiscuity and thus destroy the traditional norm of monogamy for marriage? Or should we agree with Corvino that while we must grant that "on average, sexual exclusivity appears less important for gay men's relationship success (longevity, satisfaction, etc.) than it does for that of heterosexuals or lesbians," inferring from this that legalizing gay male marriage would destroy the norm of monogamous marriage is both implausible and unjust?
It is empirically implausible to claim that the traditional norm of life-long monogamous fidelity will be destroyed if we legalize gay male marriages, some of which will not be strictly monogamous. Given the small number of gay men, and the much larger number of heterosexual men, there are probably many more heterosexual couples who become "swingers" in "open marriages" than there are promiscuous gay men. And yet even with the large number of heterosexual people who ignore the norm of sexual exclusivity, monogamous fidelity is still for most people a marital norm, if only as an ideal often violated in practice.
It is also unjust to deny gays the right to marry because some gay couples will fail to be monogamous. This is unjust because many heterosexual married couples choose not to embrace sexual fidelity as a norm for them, and yet they are just as truly married as any other legally married couple. And, again, it is unjust to use the gay male propensity to promiscuity as a reason to deny the right to marry to lesbian couples who might enforce sexual exclusivity in their marriage, or to those gay male couples who do strive for monogamous fidelity.
Nevertheless, one might question the relevance of such moral arguments to the constitutional standards enforced by the Supreme Court. And, indeed, the fourth argument of the lawyers in Baker v. Nelson for dismissing the appeal of Baker and McConnell was that there was no clear language in the Constitution of the United States giving homosexuals the right to marry. The lawyers wrote: "The framers of our Constitution and the statesmen of the States of the Union ratifying the same, would have never conceived that the protections which were afforded the people under this historic document would ever be utilized in such a way as to bring about the result sought by the appellants herein" (p. 8). This is undoubtedly true--that those who framed and ratified the Fourteenth Amendment never intended or anticipated that the guarantee of "equal protection" would be interpreted to mean that state bans on same-sex marriage were unconstitutional. But it could also be said that they would never have foreseen that the Fourteenth Amendment would be read as striking down state laws banning interracial marriage as unconstitutional, as was done in Loving v. Virginia, a decision favorably cited by the lawyers arguing against the claims of Baker and McConnell. Even if the decision in Loving cannot be grounded in the original understanding of those who framed and ratified the Fourteenth Amendment, it can be grounded in the original meaning of the words "equal protection of the laws" in that amendment, because we can see how laws prohibiting interracial marriage deprive interracial couples of equal protection in a way that does not rationally serve any legitimate interest of state government. Similarly, we can see how laws prohibiting same-sex marriages deprive homosexual couples of equal protection in an arbitrary way that does not have any rational relation to any proper purpose of government.
The fifth argument against the appeal of Baker and McConnell invoked religious belief. "Our country, and our Constitution, were founded upon basic religious principles and one of the most basic of such principles is that marriage is an institution ordained by God and that such institution is to be entered into by a man and a woman as husband and wife." The lawyers for the appellees do not explain, however, where exactly those religious principles enter the Constitution. Nor do they respond to the claim of the lawyers for Baker and McConnell that hostility to homosexuality in the Bible shows an unreasonable prejudice against homosexuals that has no constitutional status.
The final argument against Baker and McConnell's appeal points to one of the most peculiar facets of this case. The questions raised by this appeal are said to be moot, because while Baker and McConnell claim they have been denied the right to marry, they did in fact marry each other on September 3, 1971, about six weeks before the Minnesota Supreme Court ruled against their appeal!
This marriage was made possible by some clever legal maneuvering by Baker and McConnell. When they realized that adoption would give them about 90 percent of the benefits of marriage, because the adoptee becomes part of a family, they arranged to have Baker adopted by McConnell. Also, in the process of adoption, they changed Jack Baker's name to Pat Lyn McConnell, so that the gender free name "Pat Lyn" would make it harder to identify them as two men when they applied for a marriage license. They then moved for a short time to Mankato, Minnesota, in Blue Earth County, where they applied and received a marriage license for Michael McConnell and Pat Lyn McConnell on August 9, 1971. They married a month later in Minneapolis. They could then claim that when the state supreme court later ruled against their Hennepin County license, this would not deny the legality of their wedding.
In their book about their life, published in 2016, six months after the Obergefell ruling, McConnell and Baker tell the story of a marriage that has now lasted for 48 years. While recognizing that most gay men seek only short-term relationships, they decided that they would be one of those few gay male couples who would make a lifelong commitment to one another. They admit, however, that they did not see this marital commitment to one another as requiring sexual exclusivity. They agreed that they would be free to date other men (McConnell et al. 2016, 15, 38-39, 50-51). Here then they confirmed Symons' point about the promiscuity of male homosexual sexuality. But they also indicate that as they grew older, the gay bars and bathhouses were less appealing to them, and they settled into a largely monogamous marriage lasting a lifetime. They thus achieved the first natural end of marriage--conjugal bonding, or what Corvino has called the "mutual lifelong caregiving" function of marriage (Corvino and Gallagher 2012, 14-18).
A Video on the Gay Marriage of McConnell and Baker
They also sought the second natural end of marriage--the parental care of children. For over two years, they tried to adopt a child. They decided that they would be open to adopting any child under the age of 6, even one that might need special care. But when all of their applications at the adoption agencies failed, they finally decided that their marriage would be childless.
Michael McConnell and Jack Baker have not achieved the ideal marriage of a couple with lifelong perfect monogamy and the rearing of children. But it's hard to believe--as many opponents of same-sex marriage would say--that this is not a "real marriage."
Appellant's Jurisdictional Statement, Baker v. Nelson, U.S. Supreme Court docket no. 71-1027.
Appellee's Motion to Dismiss Appeal and Brief, Baker v. Nelson, U.S. Supreme Court docket no. 71-1027.
Arkes, Hadley. 1993. "The Closet Straight." National Review, July 5.
Bravin, Jess. 2015. "Supreme Court Clerk Remembers First Same-Sex Marriage Case." The Wall Street Journal, May 1.
Buss, David. 2016. The Evolution of Desire: Strategies of Human Mating. Revised and updated edition. New York: Basic Books.
Corvino, John, and Maggie Gallagher. 2012. Debating Same-Sex Marriage. Oxford: Oxford University Press.
Frank, Nathaniel. 2017. Awakening: How Gays and Lesbians Brought Marriage Equality to America. Cambridge, MA: Harvard University Press.
McConnell, Michael, Jack Baker, and Gail Langer Karwoski. 2016. The Wedding Heard 'Round the World: America's First Gay Marriage. Minneapolis: University of Minnesota Press.
Symons, Donald. 1979. The Evolution of Human Sexuality. Oxford: Oxford University Press.
Trivers, Robert. 1972. "Parental Investment and Sexual Selection." In Bernard Campbell, ed., Sexual Selection and the Descent of Man, 1871-1971, 136-79. Chicago: Aldine.