First, is the purely biological issue. Procreation. The nation state does have interest in increasing and maintaining population. You won't have that happening, without technical support, in a same sex couple. Sorry, I can't change that.
sterile people can't reproduced either and they can get married. irrelevant.
Second is the legal reason, which I'm surprised no one has raised. We have an overburdened legal system. We are effectively creating contracts. Some of those contracts will terminate prior to the death of one of the parties. That will create more court cases. As a corollary to that, we have substancial caselaw and statute on different sex marraige. Those, because of biological difference, may not apply and we'll have to grow another system to habdle it. Who gets the alimony, for example?
so we cover this in the marriage laws. lots of things cause legal troubles. that's why we have a system. it's not worth removing rights from a portion of the population
Third is the idea that families, in a traditional sense, do provide some stability for society. A same sex couple in not going to look at the societal values, e.g. public education, in the same light as different sex couples. The latter will have more of a stake is these societial values than the former.
and what harm comes from this. List some actual problems that come from this "lack of stability in society" nonsense.
Fourth is political. I strongly oppose on a matter of principle that because MA permits it that PA should be forced to as well.
And if MA wants to permit interracial marriages, MS shouldn't be forced to as well.
I'm suprised no Republican has answered the original question. Come on Phil, tell me how gays love Santorum too, just as there are supposedly loads of Kerry voters who worship at his feet.