Here's where I'm "at" as a Muslim in regard to homosexuality: I accept the orthodox ruling that homosexual acts are forbidden. (Being straight, this isn't really any sort of special challenge) The Quran and hadith are abundantly clear on this point, more clear than the Bible in fact. For example, Bible-believers who want to argue that the story of Sodom and Gomorrah is not really about homosexuality actually have some ammunition in passages such as:
Behold, this was the guilt of your sister Sodom: she and her daughters had pride, surfeit of food, and prosperous ease, but did not aid the poor and needy. They were haughty, and did abominable things before me; therefore I removed them, when I saw it [Ezekiel 16:49-50]
while in the Quran the men of Sodom are addressed differently saying: "Most surely you come to males in lust besides females; nay you are an extravagant people." [7.81] or again "What! do you indeed approach men lustfully rather than women? Nay, you are a people who act ignorantly." [27.55]
At the same time, I also don't really have much of a visceral reaction ("ick response") to homosexuality either. And much of the time I find "natural law" type arguments unconvincing.
That said, the following thoughts recently occurred to me as a way of framing some of these issues:
Suppose you are in a society where blood is thicker than water and people locate a great part of their identity in their biological families; e.g. Lannister, Stark, Capulet, Montague, Hattfield, McCoy (And many "traditional" stances assume this as an axiom). Then marriages don't just involve the couple getting married but they have political implications for both families (and so "arranged" marriages make a certain amount of sense). Furthermore, one of the important functions of marriage in such an environment is to create concrete natural connections between families through children (a new grandchild, cousin, etc. common to both sides).
But, in a really fundamental way, gay marriage can't play that role. Even when the gay couple "has" children, at least one family, possibly both, aren't getting a new blood relative. (and the child is possibly disconnected from some of its biological relatives). So from a traditional perspective, gay marriage is ultimately incomplete. Instead of being about families being joined, gay marriage is more fundamentally about the sex lives of the individual couple.
To be fair, people's feelings about marriage and family have been changing for a while now in various ways (e.g. towards greater individualism, increasing divorce rates, changing attitudes about adoption, limits on parental rights etc.) which probably has softened the ground for gay marriage. New reproductive technologies have allowed for surrogate mothers, sperm donors, egg donors to all be distinct from "mom" and "dad". Gay marriage is just one more thing bringing us one step closer towards Huxley's Brave New World where biological lineage and reproduction are separated from family and emotional relationships.
