The concept that demographic factors don't confer favored status upon somebody is a pretty basic Christian teaching, but many Christians are still gonna be loathe to condone same-sex marriages. Equality between men & women is tricky: men & women can be seen as equal in Christ, but they can also just as easily be seen as having different roles to play in the life of the church.
I just wonder how people can argue that gender alone can determine them having different roles to play in the church. It shouldn't matter more than a person's skin color, which is not at all.