Let me be devil's advocate: can you marry your sister or mother?Let me play "devil's advocate" for a moment here. As I understand it, it would be illegal to marry a first cousin. Does that, then, not discriminate based on family relationship? I mean, you can't control who you love. Right?
Government should get out of marriage all together, not sanction it, not recognize it. Nothing.
IMHO, law should be secular. Marriage is religious. The conflict is the mixing.