Firstly, let me preface this by stressing that I in no way advocate this position. But the only non-religion-based argument I know of against gay marriage is that only one male and one female can procreate, therefore any other "union" is unnatural and should not be recognized by the state.
Of course this means old people should not be allowed to marry.
And people with infertility issues!
no worries, I completely agree with you.
The only argument I've heard of is the argument from defintion. Flaw with that is, many dictionaries have amended their definition of marriage to actually included same sex marriage and also civil partnerships.
I believe the only thing defining marriage as being between a man and a woman are religious doctrines. Making any law that respects that as the definition of marriage violates the 1st and 3rd part of the Lemon test, which is what is used to find out of a law satisfies the establishment clause of the first amendment. Basically, they shouldn't have been able to pass the Defense of Marriage Act. I don't know how they did not clearly see that this law provokes religious/government entanglement.
Most religions have traditionally defined marriage as between man and woman, have they not? Did Buddhism and Islam and Shinto and Christianity all conspire together, or is it more basic and universal than that. I mean, you seem to believe in what amounts to a huge coincidence. It might have a Jungian basis. Just sayin'.
My guess is that it could be modeled on the Hammurabi Code's definition of marriage.
In any case definitions can be altered to fit the modern era. The definition of homosexual has be amended after it was discovered that it is not a disorder.
What is typically not brought up during this debate, however, is that while the bible defines marriage as between a man and a woman, throughout the bible there are several acceptable forms of marriage. Some of these are: a man having a wife and concubines, a man, his wife, and her property (which could include slaves), polygamy, a man and his brothers widow, a rapist and his victim (as long as the rapist pays the woman's father for property loss), etc. Christians, however, do not use these as examples when defining marriage.
This is one of those issues where I'm torn. It seems to come down to an argument over the definition of a word. If we want to have "marriage" mean the union between a man and a women, then that's what it means. Of course, it doesn't mean that we wouldn't (and shouldn't) grant ALL the legal benefits to same sex union couples.
But then again, we could simply change the meaning of the word (and digress the conversation into a matter of prescriptive vs descriptive linguistics... )