Maybe, maybe not, but soon we'll not only have same sex marriage, followed by same sex sibling marriage and the states will start scrambling to create legislation to stop it and all sibling marriage.
Truth
Gay marriage is a done deal. Nothing they can do about that. As for incest marriage, it's traditional so they'll have to fight that out in the courts. Either way, you have no rational reason against gay marriage, which means your opposition is irrational.
Oh I do, it leads to a legal paradox that opens the door to same sex sibling marriage, and since that discriminates againt heterosexuals (based on their ability to procreate) a good chance that all sibling marriage become legal.
Nope, don't like it.
Oh and by the way, should SSM become law, the arguments for it would be EXACTLY the same all along the line.