I'm supposing that in the early years when villages were small and distant, and marriages were arranged, or at least planned when there were only few boys and girls of proximate age available to be joined at any particular time, the purpose was to keep the tribe going. Religion was the set of civil laws (separate from the physical laws) that kept rule and order in place for fear of a higher punishment. Marriage was a way of designating that a woman was "off limits" to others if an ordered society was to exist and sustain.
Today's concept of homosexual marriage arose (again in my opinion) from workplace discrimination and harrassment laws. The argument at the time was that heterosexual couples could freely discuss their weekend activities, such as when taking children to sports events and parties, while gay workers were not similarly free to discuss their activites (perhaps they were even still "in the closet" at the time). Heterosexual couples could discuss going out with their wives/husbands, have family pictures on their desks, etc., while gay couples did not feel similarly free to express their own social arrangements. In fact, heterosexual displays of their familial arrangements were (and are still) so much the norm that they don't even feel that what they do is an overt expression of their sexuality, even though their sexuality is implied by their displays of family. Gays were simply asking for the same ability to express their familial arrangements as commonly, and as taken for granted, as heterosexuals do.
The idea that what they have is "marriage" is an attempt to equivalize their relationship with heterosexuals, when history is against that concept. Perhaps the answer is to decouple religious marriage from civil unions and require that all couples appear before a judge to obtain a civil union regardless of religious marital status, in other words, no longer make legal a church marriage. People of religious faith would still have their church/synagogue weddings, but would also have to separately seek a civil union in order to obtain legal status.
-PJ
You may have a point, although I think G-d ordained marriage or man would have never put up with it. But homosexuals have already won the ability to talk openly about their relationships. They have won to the point where the majority support civil unions - even the majority of Christians.
Have you heard that the debate over the Defence of Marriage ammendment is about wheter to include or exclude a clause banning civil unions? And that's among the religious.
Once again, this doesn't explain our attachment to the word "marriage." It walks, talks, and quacks like a duck. I understand the church being against homosexual marriage. But I don't understand the church being in favor of homosexual civil unions. Can they really be saying 'the Bible is against homosexual marriage, but not against state sanctioned civil unions?' I can't make it add up.
Shalom.