Gays, lesbians, bisexuals

[The Wizard from Milan]

inked,
The trouble is that we start from such a different ethical positions.

I don't know whether sexual orientation is nature or nurture or both, but I know that my orientation was already fixed at puberty (because I remember being sexually attracted to boys since the inception of puberty, and completely indifferent towards girls). As you seem to agree with me, I still had three choices of acts: same-sex, different-sex, celibacy. You seem to call this a choice and we agree on that. I agree that the choice to act (or not to act) upon one's orientation is a choice.
But I did not have any expectation to enjoy the three choices equally. My point is that I did not choose to enjoy more same-sex acts than different-sex acts, that was exogenously determined. That is what I say is not a choice. You seem to agree on that, but I would like to see a clearer statement.
I consider the choice of following my natural inclination (or exogenous taste) as perfectly legitimate. You do not seem agree for some ethical reason (which I am not sure you have explained, but I assume is religious of some sort). But here the crux of the disagreement rests. Because I do not recognize any religious system, nor do I recognize ethical systems that forbid acts that have no third-party effects. I actually denounce as immoral the proposing of pseudo-ethical (as I call them) systems that forbid acts with no third-party effects.

Marriage is a related but separate sort of question. I don't believe one can talk of a wester view of marriage, because marriage is a very different thing in different time and different places in the west. The wife was a slave in some times of the roman empire and was still the "subjected to the husband will" (although not a slave) in italy up to 1972.
John Boswell has fund evidence of same-sex marriages celebrated by the church in medieval time.
Moreover, I don't think that the traditional view has any relevance.
I simply don't think married couples should have any rights more than single people. They should have, of course, the right to visit each other in hospitals..., but no special rights.
I also think that same-sex married couples should have the same rightes than different-sex married couples, because I don't think the sex of the spouse should matter.
Same sex-marriage is related but not identical to a sexual orientation issue, because (as some conservatives would tell you, correctly) gay e lesbians can still marry heterosexually (conservatives just don't seem to grasp the implication of this though: mismatched-orientation couples undermine the traditional view of the family much more than same-sex couples)