I heard recently from a friend in a PM that he/she wasn’t completely sure where he/she stood on the gay marriage issue. I decided to do my bit and lay out the issues as I see them in a reply PM. That PM was the basis for this post, though the post has more content.
I apologize for any sloppiness on my part in how interchangeably I've used "gay" and "LGBTQ."
The first question is the extent to which we allow religious objections to decide government policy. For a variety of reasons that should be obvious, I'm not in favor of that.
Marriage is an interesting institution in this regard because it can be performed either by clergy or by a justice of the peace, and it has both religious and civil/legal ramifications. We don't currently separate these. If we did, we'd probably call the religious ceremony "marriage" and the civil ceremony "civil union." If we were to decide on civil unions for gays, the sensible thing for equity reasons would be for all marriages performed by government officials to be redefined as civil unions, but there isn't much of a constituency for that, aside from which there is a whole body of marriage law already in place that it makes no sense to rewrite.
Regardless of what the law states wherever you live, no one that I know of is contemplating forcing clergy to perform gay marriages under any circumstances. Clergy can already refuse to perform all sorts of marriages for religions reasons, such as interfaith marriages. That won't change, so legalizing gay marriage doesn’t involve taking choice away from religious institutions.
So, why else might one want to prohibit gay marriage?
1. Because of the potential effects of gay parenthood. This subdivides into two issues. The first is the worry that gay parents would produce gay offspring. (I’m afraid we have to assume that anyone opposing gay marriage thinks homosexuality is a negative outcome in some respect, though in what respect ranges from concerns over a hostile environment to active hostility toward the LGBTQ population.) There is no statistical evidence to support this at all, and we know that most gay people come from straight parents. The only difference here is that having gay parents might make it easier to come out of the closet if one is already gay, but that's about tolerance, not orientation.
The second is allegations of inferior parenting in some other way. There is no data to support this and, frankly, we don‘t screen heterosexuals before we allow them to become parents, so there‘s no standard in current use to meet even theoretically. (Even if such data existed, it would involve differences in some sort of central tendency such as median, not an absolute; in other words, the probability that all parents in one category would outperform all parents in the other is functionally zero.) In many ways this wouldn‘t be a relevant question even if we had a standard in place: What makes anyone think that most children adopted by or born to gay couples have a choice of being brought up by straight couples to begin with? Anyone who thinks that being brought up in foster care (the more realistic alternative) is superior to being brought up by gay parents would have to be either self-deluding or a complete idiot.
2. Because the purpose of marriage is reproduction. Personally, I'd say raising children is probably a more important issue here than producing them, which I've already addressed, but let's look at this. We marry heterosexual couples who choose not to have children or are infertile. We marry people who are too old to have kids. We're not following this standard now, so it makes no sense to impose it on this issue.
3. Because homosexuality is unnatural. It occurs in an awful lot of human beings, plus many other animal species. If this isn't occurring in nature, where exactly is it occurring? In a lab?
4. Because homosexuality is a choice. It may be a choice if you're bisexual, but one isn't bisexual by choice. I did not choose my orientation. I am not attracted to men at all. It's not that I chose not to be - I can't claim credit for resisting nonexistent temptation - I'm just not. If I didn't chose my orientation, I can't assume that others chose theirs. Then, of course, there's the obvious question here: Why would anyone in their right mind choose to be gay in a world so overwhelmingly hostile to homosexuality? The disadvantages so far eclipse the advantages as to be ridiculous. If you're gay, you potentially face:
Rejection by your employer
Rejection by friends when you come out
Rejection by your family
Rejection by your religious institution
and, depending on your views,
Rejection by God.
Think about this one: If you're Orthodox Jewish or fundamentalist Christian and gay, you face all sorts of agony and self-loathing. Under what circumstances would such a choice be feasible to such people?
This last point is enough of an issue that there’s a business in attempting to change orientation. It’s not a very pervasive business for the simple reason that the process doesn’t work; if it did, there would be populations (like religious fundamentalists) who would partake routinely.
Choosing homosexuality might theoretically make sense once we’re a lot closer to equality, but at the moment we’re just too far from that.
5. Because homosexuality grosses you out. Too subjective a standard for the law; we don't get to impose our tastes on everyone else.
6. Because of the slippery slope. The standard of "consenting adults" has been around for quite a while and no one, aside from maybe a few people way out on the fringes, is suggesting abandoning that standard. You can find people on the fringes to advocate anything. Legalizing gay marriage will not lead to the legal ability to marry children, pets, or your toaster.
Actually, the slippery slope argument has a flip side: In cases like the constitutional amendment about to be voted on in North Carolina, a confirmation would set a precedent of limiting the rights of a particular minority. That's one of the most dangerous slippery slopes I can think of. (Thanks to SBA for this point.)
7. Because homosexuality is pathology. Not according to the American Psychological Association.
8. Because gay marriage threatens the institution of marriage. I'd answer this objection if I understood it but I can't find anyone who can explain it to me. If gays get the ability to marry, this is supposed to affect my marriage to my wife how? This contention may be the worst of all because those advocating it feel no compulsion to explain what they mean by this - they just assert it and claim to be "protecting" marriage without specifying how gay marriage potentially threatens it.
That’s my list of the objections to gay marriage I can come up with, along with my answers. I haven’t listed advantages yet. So:
1. At a time when commitment to marriage as an institution has decreased, which most Americans would not characterize as a good thing, introducing a new population to the institution bolsters the institution. In other words, the contention that gay marriage threatens marriage as an institution is not only wrong but backward - it actually supports the institution.
2. The reasons society values the functions performed by the institution of marriage also apply to the LGBTQ population. Social stability, stable environments for children, mutual support in old age, psychological health of the population, help with medical care, limits to promiscuity that can lead to public health risks, etc. Thirty years ago we were in a lethal epidemic involving a lot of gay promiscuity, particularly among males. Gay males were condemned for that at the time and many have chosen to take such criticism to heart and to emulate their critics: settling down, getting married, raising families. That they should be condemned for being responsive and responsible is fundamentally hypocritical.
3. It’s good for business. A lot of major corporations value their LGBTQ employees and have problems when attracting and/or relocating these employees becomes difficult as a result of oppressive state laws. It’s also, of course, good for the wedding industry.
4. Legalizing gay marriage is more in keeping with values that we traditionally think of as American. Such as tolerance, equality, freedom and justice. The reverse is also true: keeping gay marriage illegal promotes intolerance, bigotry, oppression and injustice. Legalization is better for our international image and is a better example to set for our children.
5. Legalizing gay marriage increases the number of stable families available to adopt children.
I could probably come up with a few more but this is, I think, a decently functioning list.
Personally, I can’t come up with any valid objective nonreligious reasons to keep gay marriage illegal. I can’t play Sophist and take the other side because I don’t see another side, in spite of the fact that I am actively looking for it. Everything I’ve seen so far comes down to a desire to apply specific religious standards to the overall population - which is a particularly dangerous thing to do when those standards involve limitations applied selectively to a capable adult population - or a desire to apply blatantly subjective standards such as “it doesn’t feel right,” “it isn’t traditional” (neither was integration or, for that matter, abolitionism), or “it’s not natural” (which isn’t literally true). I would take an answer seriously. I’ve read a whole lot of letters to the editor, editorials, etc., and I have yet to see a decent argument opposed to gay marriage. If I ever do, maybe I’ll change aspects of my position, but I’m not holding my breath.