Mich. Comp. Laws § 551.1: Marriage between individuals of same sex as invalid contract.

Sec. 1.

Marriage is inherently a unique relationship between a man and a woman. As a matter of public policy, this state has a special interest in encouraging, supporting, and protecting that unique relationship in order to promote, among other goals, the stability and welfare of society and its children. A marriage contracted between individuals of the same sex is invalid in this state.