On Monday, June 16, San Francisco began implementing the ruling of the California Supreme Court authorizing same-sex marriages in the state. Meanwhile a state constitutional amendment negating the ruling is heading for the ballot in November and seems likely to pass.

What one thinks about these developments depends, primarily on one's concept of the nature and function of a marriage. There is no reason to believe that partisans on either side of the issue are insincere, or even unjustifiably biased.

To supporters of same-sex marriage, a "marriage" is a social and legal arrangement whereby two people affirm their love for each other and undertake commitments that include (normally) certain obligations: sexual fidelity and the duty to care for one's partner in crises, including health problems, financial distress and the like. There is no obvious reason why two people of the same sex may not enter into such reciprocal relations, and many do.

Opponents of same-sex marriage have a different concept of the meaning of the word "marriage." Drawing on historical precedent, they conceive of a marriage as a specific institution with very explicit rules, which apply whether the marriage is strictly "civil" or heavily impregnated with religious overtones. The institution is relatively difficult to dissolve and involves explicit obligations of mutual support -- not only financial, but in the broadest sense social. Above all, it is designed to provide the optimum environment for the raising of children, which is, of course, a matter of paramount interest to society as a whole.

It is for this latter reason that marriage, as traditionally conceived, is always between a man and a woman. They may not actually have children, but the possibility is always, at least theoretically, there. A same-sex couple may, of course, adopt and raise children, and many do, but it is not an integral aspect of their relationship.

These are the considerations that make many sincere people balk at the notion of same-sex marriage. Such a "marriage" can certainly be based on love, and even entail the adoption and raising of children, but it cannot, by definition, eventuate in children generated by the couple in question. Does that matter?

I see no easy answer to the question. It is simply (as I said above) a question of how we define the word "marriage." To many people, the civil and/or religious union of two people who cannot have children falls short of their definition of marriage. To others, it may be a misfortune -- even a tragedy -- or not; but it doesn't invalidate the marriage.

The only question really up for decision is how society as a whole shall view these two concepts of the word. Should it confer the word, and the concept, on any fully committed relationship between two people who love each other? Or should the word "marriage" be reserved for the relationship between a man and a woman who are, at least theoretically, capable of having children and raising a family?

Personally, I would not be opposed to the latter solution. It would preserve the word "marriage" for relationships of the traditional sort, thus continuing to confer upon it a particular status. Say a "higher" status if you wish (as do those who object to the idea), but, if so, it is a status that every society has recognized as promoting its own survival.

But I recognize, too, that such a status is not desirable, or even possible, for many people who regard their own status as devalued as a result. And it seems clear that many Americans, in what they regard as a spirit of fairness, are moving toward recognizing the word "marriage" as applying to any two people who want to use it to define their own particular relationship.