Jim,
It depends what you think marriage is for. If marriage is simply an event to celebrate committment, then of course nobody should be discriminated against. If marriage is society's way of encouraging and supporting unions that create stable homes for kids, then the kids' interests have to be paramount, not the perceived rights of adults who feel left out.
I'm not sure whether there is evidence that gay couples make better or worse parents. There is ample evidence that kids in a home with male and female "parent" do better than those where the father figure is absent. Some brave other person can suggest whether this is relevant to gay marriages that exclude a father figure, or that have two of them ;-)
FWIW, gay marriage was legalized in New Zealand yesterday.
Regards
j.R
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
