The original and ongoing purpose of marriage is to identify the father of a woman's children. He is expected to take responsibility when the pregnant woman is vulnerable, and contribute to the children's upbringing. So marriage was never a right, it was always a duty, for both the man and the woman, and of course, love makes it better. In this context, gays don't need what every heterosexual traditionally needs from marriage, and you can see gay marriage actually redefines it, fundamentally. Without a doubt, gay people need validation of their relationships, rights of inheritance, visitation in hospitals, and religion should protect them from harrassment, but they don't have the same problem as heterosexuals, as just described. Based on the original model, gays don't actually need marriage per se.  Civil unions?