Is childless Marriage beneficial to society?

(Note: In connection with this post, please read Lawrence Auster's entry on the extreme radicalism of homosexual marriage. Scroll down and read Dana W.'s remarks and LA's reply to Dana on no-fault divorce, an issue I thought about adding to this entry but ultimately decided against.)

MARRIAGE, n. The act of uniting a man and a woman for life; wedlock; the legal union of a man and a woman for life. Marriage is a contract both civil and religious, by which the parties engage to live together in mutual affection and fidelity, till death shall separate them. Marriage was instituted by God himself for the purpose of preventing the promiscuous intercourse of the sexes, for promoting domestic felicity, and for securing the maintenance and education of children.(emphasis mine)

(Definition taken from Webster's 1828 American Dictionary of the English Language)

Contrast Webster's definition with an opinion expressed at Savage's blog on the purpose of marriage and why government benefits related to marriage should be strictly tied to having children. (Admittedly, when you start talking about government benefits passed out to folks who meet certain government-established criteria, I start to get a little nervous. As they say, "there ain't nothin' free," so one has to decide whether the rewards outweigh the costs. I think generally they don't when it comes to government favors.)

My parenthetical remarks aside, though, do you think that government benefits related to marriage should be reserved only to those married (husband and wife, male and female, man and woman) couples who have offspring; that government benefits for married couples should be tied to having children? That seems to be the consensus of some at BNWW and elsewhere. John quotes commenter Robert Hume from the Inductivist who writes in favor of this view:

The main purpose of marriage in modern times is as a support system for children. The state grants benefits to married folk in order to help raise children well.

It used to be that all married people had children, so the benefits were not mis-allocated. But now many heterosexual couples do not have children, so they reap benefits to which they are not entitled.

So homosexuals have noted that there were benefits that they could not get that heterosexuals could get … without carrying the responsibility of caring for children.

In this case homosexuals have a good “equal protection” argument.

The solution is to modify the law to tie marriage benefits to having children, not to being married.

The presumption is that society reaps little or no benefits from the institution of marriage except those which are directly related to the having and raising of children, and therefore, since society derives no appreciable benefits from the institution of marriage aside from the production of offspring, and since homosexuals can't have children which are a product of both partners, all government favors related to marriage must be changed to apply strictly to marital reproduction. So you've essentially killed two birds with one stone in Hume's opinion; you've stopped the mis-allocation of government marriage benefits to people who are not entitled to them (childless couples), and you've prevented by the same stroke homosexual marriages.

I simply have to disagree with this. Marriage between a man and a woman is beneficial to society in precisely the ways that Webster lays forth in his definition of the term -- it helps to prevent the promiscuous intercourse of the sexes, and promotes domestic happiness. So, while I'm not saying that government benefits related to marriage should be equal across the board (unless they're equally zero), I am saying that marriage between men and women is beneficial to society apart from having children. And if society is going to reward people for their particular contribution to the general welfare and encourage its continuance, it ought to reward childless married couples for theirs.