There's no reason the term marriage should just be for a man and a woman.
I can't word this the right way, so it may not make much sense. But, it's a bit prejudice to say that gay couples should have to say they're civilly joined or some crap, when normal couples can say they're married. Marriage has gone back long before we wrote the term as "a man and a woman."
Same sex marriage dates back as far as Ancient Egypt (Kemet). Recognition of it in Western culture dates back to early in the Middle Ages. Polygamist marriage dates back to long before recorded history.
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The fact that now because of certain dominant religions, people believe they can impose their beliefs on everyone... Well, it's a bit prideful and arrogant. Christians, Islam and Judaism didn't invent marriage. They should have no say over the word nor the use thereof. Church and State should remain separated, and when we start trying to impose Religious beliefs into our State beliefs, then that's when bad things start happening.
Religions can control the marriage ceremonies themselves. Non-religious marriages should be able to marry with their own type of ceremony that they happen to desire or with none at all, if they should so wish it. Personally, while I'm not religious myself nor would I want a a Christian wedding with all that it implies religiously and all of the spouted religious nonsense, I think ceremony is good. Like the ceremony in Braveheart. Beautiful, yet not really religious. Or it may have been, I don't really remember. But none of that is really the point.
The point of marriage is a recognition of one another as a couple between both yourselves, society, and recognition of that position by the State, whereupon certain legal rights shall be granted.
It's marriage, and people shouldn't be such prudes over how the word's used.
Honestly, the definition should be changed to "between two sentient beings" or some such, in such a wording that would allow future marriages with intelligent extraterrestrial life. But, not animals... Beings capable of communication, reason, and whatnot. May as well future-proof it. That's what I think anyways.