Mo. Rev. Stat. § 454.1590
Nonparentage as defense.
454.1590. Nonparentage as defense. — A party whose parentage of a child has been previously determined by or pursuant to law may not plead nonparentage as a defense to a proceeding under sections 454.1500 to 454.1728 .
(L. 2011 H.B. 260) Effective 6-15-16, see § 454.1728