Yes married homosexuals are more stable than single homosexuals. The deserve financial benefits equal to what straight couples get because the value to society is the same.
I agree sexual intercourse is a behavior but I do not believe that is the sole definer of who is gay and who is not. I think most people would agree you can be straight before you lose your virginity. The societal benefits of marriage do not require that the couple have sex so why should that even enter the equation. I can respect your states rights position even though I don't agree with it.
High divorce rates may lessen the good impact of marriage but do not completely nullify it either. Whether love and devotion should be incentive enough is irrelevant. Government has to deal with reality and so they incentivize the things they want more of.
David already answered this but I will reiterate... gay marriage doesn't make people gay. The questions is are married gay people more stable than single gay people? I believe the answer is yes.









