Mo. Rev. Stat. § 532.370
In all cases where it shall appear from the evidence in any proceedings in habeas corpus, instituted between husband and wife for the custody of their children under the age of fourteen years, that by reason of insanity, drunkenness, cruelty, or other cause, the party against whom the complaint is brought is unfit to have the care and government of the child or children in controversy, it shall be lawful for the court hearing said cause to award the custody of the same to the complainant or other guardian, as shall be deemed best in the premises, and to make such other orders touching the custody and control of such child or children as the court may deem proper; and the order or decree of court touching said custody shall be valid and remain in force during any period within the minority of said child or children, which shall be fixed by said court; and any person at any time violating said order or decree may be dealt with summarily for contempt.
§ 532.370, RSMo