Historically, in Native American tribal societies, a berdache marriage was a recognized union between persons of the same sex.
Question: For those against "redefining" marriage, do you know anything about the Nuer tribe...? ...and/or various Native American tribes and/or ancient Japan?
In the African Nuer tribe, it was common practice for barren women to divorce their husbands and go marry another woman. If the couple requested it, a surrogate mother would give birth to their child.
Berdache (I'd prefer to use a more proper word, but regrettably, one does not exist) was common practice among Native American tribes, in which gay men were permitted to become the "wives" of other men. These men were highly respected, often being healers, storytellers and religious leaders.
In ancient Japanese culture, love between two men was considered to be love in its purest form.
Really, what makes you think that you have a right to claim that the marriages in these cultures were wrong? They were existing far before the Bible was written! Psh... "redefining" marriage... we redefine marriage every 50 years anyway.
(By the way, I know that many Christians are not opposed to gay marriage. This was not directed at you.)
Kevin: Actually, homosexuality has been observed multiple times in nature among 1500+ species (generally the most advanced... such as humans, chimpanzees, zebras, dolphins, dogs, cats, etc.). If you don't consider that natural, then I don't know what to do with you.
Some links for further reading, if anybody's interested:
Nuer tribe
http://anthro.palomar.edu/marriage/marriage_4.htm
Berdache
http://www.nu-woman.com/berdache.htm
Ancient Japan
http://www.bambooweb.com/articles/H/o/Homosexuality_in_Japan.html
Answer: Your information is correct. To add to it, same sex marriage was also recognize in Polynesian culture prior to the arrival of Europeans.
There is a tribe in the Amazon that has always practiced polyandry as the sole form of marriage: one woman with many husbands.
So marriage has existed, and continues to exist, in many forms, defined by the culture, and not "owned" by any one religion.