Incidentally, this avoids two of the major flaws in Josh's logic, notably the arguments that if all men are said to be less faithful, and hence less nurturing, than all women, then heterosexual marriage itself is unstable and unsustainable--and, on current divorce rates, a great many of them may be, though not necessarily because of infidelity--and, second, Josh's argumentation must lead him to endorse lesbian marriage, even if he opposes gay unions.

This is true, but my post wasn't intended to concern nurturing's impact on the legality of homosexual marriages, but rather its impact on the simple chemistry of homosexual relationships/marriages.

Concerning the faithfulness of men and women, and their nurturing capabilities, I would note that I offered one criticism of my argument in the footnotes. But I still think there are physiological facts to support it.

Oxytocin comes to mind. This hormone creates a bonding response when a mother is nursing her child, but is also released during intimacy. Here is physical evidence that women become emotionally bonded to their sexual partners even if they only intend a more casual encounter. Wouldn't this have significant implications for nurturing? And doesn't this in fact support the notion that women, generally speaking but not always, do in fact have a nurturing instinct?

Oxytocin, as far as I can determine, is a wonder hormone perfectly suited for a certain sort of neotraditionalist argument for marriage. That oxytocin can occasionally be overcome (as in the infidelity experiments in the post) suggest that its importance is easily exaggerated.

its impact on the simple chemistry of homosexual relationships/marriages....Here is physical evidence that women become emotionally bonded to their sexual partners even if they only intend a more casual encounter.

Here, though, we are no longer talking about "homosexual" relationships or marriages, unless oxytocin is released only during male-female intercourse (which would be remarkable). We are, instead, discussing gay relationships, and it is best to be upfront about this fact, because under both the initial terms of the debate and the terms of the rebuttal, lesbian relationships will most likely be far more nurturing than male-female (this, incidentally, suggests that Jason's emphasis on nurturing as a basis for marriage is an incomplete point: it is not nurturing alone, but nurturing in the context of a sexual relationship, that defines a companionate marriage).

The point raised by a commenter on your post, and anticipate in mine, is that homosexual marriages will be self-selecting for potential partners who are more likely to value nurturing and fidelity. So from a normative point of view--and, ultimately, this is a normative argument--there is no reason to deny gay men the chance to enter into unions.

Well, again, I wasn't intending to use nurturing as an argument to deny gay men the choice to enter into unions. Indeed if you recall I favor the government getting out of the marriage busienss altogether. Instead it was a sociological question. Perhaps it would help if I removed "marriage" and replaced it with "relationship." My point was one of the most basic of them all - if nurturing is as vital to a relationship as Jason argues, and I agree with him to a certain extent, then how do we account for differences among the sexes.

Good post.

Point of information: Josh, you seem to be implying that only in males does oxytocin link sex and feelings of intimacy/bonding. In fact, though, it is released in both males and females during orgasm, and is said to facilitate sperm transport during ejaculation.

Eh, this two cents is probably too late, but isn't Reproduction the elephant in the room on this discussion? Part, if not all, of marriage is to keep society going via the only way to do this, a man and woman having a child. The fact that the infertile get married is incidental to this, being that the ability to immediately diagnose infertility is a quite recent advancement. But we have these advancements now, scientifically and socially, and there are many children who can benefit from adoption. So lets make adjustments for them, civil unions and such, and leave the definition of marriage to what it always has been, a husband and wife as precusor to a family.