Mo. Rev. Stat. § 451.022
(L. 1996 S.B. 768 § 6, A.L. 2001 H.B. 157)
(1998) Section is unconstitutional because title of bill was not clearly stated and bill contained more than one subject. St. Louis Health Care Network v. State, 968 S.W.2d 145 (Mo.banc).
(2014) Section is unconstitutional under the federal due process clause as significantly interfering with the fundamental right of marriage and creates a gender-based classification that is unconstitutional under the federal equal protection clause. Lawson v. Kelly, 58 F.Supp.3d 923 (W.D.Mo.).
(2014) The right to marry is a fundamental right inherent in the liberty of the person, and under the Due Process and Equal Protection Clauses of the Fourteenth Amendment couples of the same sex may not be deprived of that right and that liberty. Obergefell v. Hodges, 135 S.Ct. 2584.