Originally Posted by RyeBread
Why stop at two, let's bring back multiple spouses and communal living?
How about Brother/Sister? Mother/Son? Father/Daughter, Granny/Grandson, etc., etc.
In the past when I have proposed the above, I get repulsive "ewww" looks from people that openly support Gay Marriage under the guise of, "but they're two willing, consenting adults..." as their excuse for supporting Gay Marriage - but they refuse to see the logic flaw and their own bigotry if they also don't support incestual relationships... etc.
I don't believe it is anyone's right to deny people the right to be a legal couple. If I had to consider the example you give, I don't think I could oppose a incestual union either - providing there were no children from natural birth.
There is scientific fact behind heath problems from inbreeding, but as far as I know, there is no evidence gay parents transform their children into gay adults.