Mo. Rev. Stat. § 211.444

The juvenile court may, upon petition of the juvenile officer or a child-placing agency licensed under sections 210.481 to 210.536 in conjunction with a placement with such agency under subsection 6 of section 453.010 or a private attorney filing a petition for adoption under the provisions of chapter 453, terminate the rights of a parent or receive the consent to a specific adoption or waiver of consent to adoption executed by a parent or named father to a child, including a child who is a ward of the court, if the court finds that such termination, consent to a specific adoption, or waiver of consent to adoption is in the best interests of the child, and the parent or named father has, in a properly executed writing under section 453.030 or 453.050, consented to the termination of his or her parental rights, consented to a specific adoption, or waived consent to adoption.