Mo. Rev. Stat. § 453.015: Definitions.

As used in sections 453.010 to 453.400, the following terms mean:

(1) "Minor" or "child" , any person who has not attained the age of eighteen years or any person in the custody of the children's division who has not attained the age of twenty-one;

(2) "Parent" , a birth parent or parents of a child, including the putative father of the child, as well as the husband of a birth mother at the time the child was conceived, or a parent or parents of a child by adoption. The putative father shall have no legal relationship unless he has acknowledged the child as his own by affirmatively asserting his paternity;

(3) "Post adoption contact agreement" , a voluntary written agreement executed by one or both of a child's birth parents and each adoptive parent describing future contact between the parties to the agreement and the child; provided, that such agreement shall be approved by the court under subsection 4 of section 453.080;

(4) "Putative father" , the alleged or presumed father of a child including a person who has filed a notice of intent to claim paternity with the putative father registry established in section 192.016 and a person who has filed a voluntary acknowledgment of paternity pursuant to section 193.087;

(5) "Stepparent" , the spouse of a biological or adoptive parent. The term does not include the state if the child is a ward of the state. The term does not include a person whose parental rights have been terminated.