Often people claim that the government should recognize homosexual marriages and give them the same tax benefits as straight marriages. I can only think of three possible reasons for the government to recognize or encourage (through tax benefits) marriages, either heterosexual or homosexual; interestingly none of these three reasons apply to homosexual marriage.
Reason one: Tradition. "It's traditional for the government to recognize marriages and provide tax benefits." But it's only tradition for heterosexual marriages, so that doesn't cut it, and it's not a very good reason in and off itself anyhow.
Reason two: Religious Observation. "It's a God-ordained religious observation." I'm not aware of any major religion that encourages homosexual marriages. If you start getting into some of the more obscure (at least in the western world) religions you get some where homosexual sex is at very least allowed, but I'm not aware of a single one where homosexual marriages or similar long term relationships are considered a religious observation. Also I'm a little uncomfortable with the idea of the government providing special protection to something if it's only purpose is a religious observation.
Reason three: Child Rearing. "It's widely believed (and supported by research) that children have the best chance of developing well if they have both a strong male and female influence in their lives, so it's in the best interests of society to encourage long term heterosexual, child-rearing relationships." This is the best reason of the three for recognizing marriages, but obviously doesn't apply to homosexual relationships.
Of course there is nothing stopping a homosexual couple in most western countries from living together, giving each other rings, and calling themselves married, but there is no reason that I can think of for the government to recognize such "marriages". Perhaps I'm missing a fourth reason?
