N.Y. Dom. Rel. Law § 7

§ 7. Voidable marriages. A marriage is void from the time its nullity\nis declared by a court of competent jurisdiction if either party\nthereto:\n 1. Is under the age of legal consent, which is eighteen years;\n 2. Is incapable of consenting to a marriage for want of understanding;\n 3. Is incapable of entering into the married state from physical\ncause;\n 4. Consent to such marriage by reason of force, duress or fraud;\n 5. Has been incurably mentally ill for a period of five years or more.\n