Here's another of those conservative attempts to hold off the possibility of introducing same-sex marriage. Jeff Jacoby tries to keep the institution of marriage fixed by insisting on just one of its functions as definitive:
The essential, public purpose of marriage is to unite male and female - to bind men and women to each other and to the children that their sexual behavior may produce. It is rooted in the belief that every child needs a mother and a father. Gay marriage, whether enacted by lawmakers or imposed by judges, disconnects marriage from its most basic idea.
He starts with a conjunction - 'to unite male and female' and bind them to their biological children - but finishes only with one of the items paired. For, if marriage can unite a man and a woman, there's no reason it can't also unite a man and a man or a woman and a woman. Therefore Jacoby has to rest his case on binding the married couple to the children they produce. But as it is, some marriages don't produce children; and nearly every marriage has other important purposes and functions than producing children. So his is an attempt to freeze the institution of marriage by arbitrarily making it less than it has always been.
Jacoby reckons same-sex marriage will 'eventually collapse'. If I could be around long enough to collect on the bet or, less probably, pay out on it, I'd be willing to put up a sum of money against him on this.