Originally Posted by HC_Chief
If the state sponsors a contract (e.g. marriage), the 14th Amendment (Equal Protection clause) applies.
This can be solved via two methods: either the state must allow for "non-traditional marriages" within the confines of the law (homosexuality is not illegal, incest, polygamy, beastiality are), or the state should not sponsor and regulate marriage.
To me it's one of those issues where I don't think the government, including state governments, should get involved in anything other than as a record keeping function. It's legal for two people to get married. I don't see the logic in limiting that by gender. I understand age limits. There is a history in this country of minor women being coerced into marriage. Couple that with the legal concept of youngsters not being considered able to give consent in many situations and I think that it's a valid point.