I ask you, why are two sisters who group up and decide to live together not entitled to inheritance rights and such the same as married people? So married couples and perhaps lesbians should get this but not sisters? This is not an argument for gay marriage, it is an argument for fixing the tax law, abolishing estate taxes altogether because they are so unfair, and a simple tax code that works for people no matter if they are married, straight, gay, or even just sisters.
The tax code argument for gay marriage is an argument about a crappy tax code, not for gay marriage. I say keep our eye on the ball, the tax code is a behemoth disaster and a tool for the corrupt. Toss it out and replace it.