I don't know enough on this topic to debate it either way. But I have always wondered, maybe you guys could help me answer this. If we do allow men to marry men and women to marry women, what is stopping a man from demanding his rights to marry his sister?
Again, I'm not asking this as an attack or giving my stance on the debate. I would just like the question answered.
Biological necessity. Some very large percentage of gays (possibly all) cannot pursue happiness under a heterosexual mandate. They must seek their relationships among their own gender. To deny gay people the right to seek this happiness, by barring them from
the most basic of human institutions (one that predates agriculture) constitutes a discrimination that approaches that of
Dred Scott. Even the laws against interracial marriage (voided 35 years ago in
Loving vs Virginia) did not present this fundamental issue. One *could* find happiness with another, unjust as the laws were.
But a gay person denied the legal right to marry the whole class of persons to whom they are attracted is utterly denied this basic human bond.
Andrew Sullivan likens interracial marriage to the present issue. He's wrong. No one needs, biologically, to marry a person of a different race -- there are alternatives. That restriction is wrong on other grounds, notably no-good-reason. Polygamy, incest, etc are also devoid of this biological need -- these are simply
wants, and there are very good reasons to bar these unions. While a truly bisexual person may want to marry "one of each", they can marry one or the other, or remain single, as they choose. All married people struggle at times with monogamy -- this is simply a difference in degree, not in kind. Pedophilia and bestiality do not apply to marriage, for reasons of consent and permanence. If your "bright line" is biological need without alternative, there is no slippery slope with respect to gay marriage.
Secondly, the hidden assumption of the argument which brackets gay marriage with polygamous or incestuous marriage is that homosexuals want the right to marry anybody they love. But, of course, heterosexuals are currently denied that right. They can not marry their immediate family or all their sex partners. What homosexuals are asking for is the right to marry, not anybody they love, but
somebody they love, which is not at all the same thing.
Heterosexuals can now marry any of millions of people; even if they can't marry their parents or siblings, they have plenty of choice. Homosexuals want the same freedom, subject to the same restrictions. Currently, however, they have zero marital choice (unless, of course, they try to fool heterosexuals into marrying them — a bad idea for a lot of reasons). To ask for a comparably, but not infinitely, broad choice of partners is not unreasonable.
Does homosexuality exist? I'm pretty sure it does, and today even the Vatican accepts that some people are constitutively attracted only to members of the same sex. By contrast, no serious person claims there are people constitutively attracted only to relatives, or only to groups rather than individuals. Anyone who can love two women can also love one of them. People who insist on marrying their mother or several lovers want an additional (and weird) marital option. Homosexuals currently have no marital option at all. A demand for polygamous or incestuous marriage is thus frivolous in a way that the demand for gay marriage is not.
Suppose, though, that someone insists that he can't be happy without several spouses, and that this is a basic constitutive need for him. Or suppose he says he can't be happy unless he marries a close relative. For argument's sake, let's say we believe him. Shouldn't at least this person be allowed to marry two people, or his father?
No. The reason is that, from society's point of view, the main purpose of marriage is not, and never has been, to sanctify love. If the point of marriage were to let everybody seek his ultimate amorous fulfillment, then adultery would be a standard part of the marital package. In fact, society doesn't much care whether spouses love each other, as long as they meet their marital obligations. The purpose of secular marriage, rather, is to bond as many people as possible into committed, stable relationships. Such little societies-within-society not only provide the best environment for raising children, they also domesticate men and ensure that most people have someone whose "job" is to look after them.
Polygamy radically undermines this goal, because if one man has two wives, it follows that some other man has no wife. As Robert Wright notes in his book
The Moral Animal, the result is that many low-status males end up unable to wed and dangerously restless. Over time, a society can sanction polygamy only if it is prepared to use harsh measures to repress a menacing underclass of spouseless men. It is no coincidence that no liberal countries have been polygamous, and no polygamous countries have been liberal. In that respect, the one-partner-each rule stands at the very core of a liberal society, by making marriage a goal that everyone can aspire to. Gay marriage, note, is fully in keeping with liberalism's inclusive aspirations. Polygamy absolutely is not.
Incest, of course, may produce impaired children. But incestuous marriage is a horrible idea for a much bigger reason than that. Imagine a society where parents and children viewed each other as potential mates. Just for a start, every child would grow up wondering whether his parents had sexual designs on him, or were "grooming" him as a future spouse. Holding open the prospect of incestuous marriage would devastate family life by, effectively, legitimizing sexual predation within it.
The rather peculiar idea underlying the "If gay marriage, then polygamy" argument is that, at bottom, there really is no very good reason to be against polygamy other than tradition — you just have to be blindly against it, and ditto for gay marriage. But there are ample grounds to oppose polygamous and incestuous marriage, grounds that have nothing to do with whether gay people will be allowed to partake of society's most stabilizing, civilizing institution. I don't ask to break the rules that we all depend on. I just want to be allowed to follow them.