Mo. Rev. Stat. § 568.020 : CRIMES AND PUNISHMENT; PEACE OFFICERS AND PUBLIC DEFENDERS — Offenses Against the Family —INCEST — Incest - penalty TEXT PDF 1. A person commits the offense of incest if he or she marries or purports to marry or engages in sexual intercourse or deviate sexual intercourse with a person he or she knows to be, without regard to legitimacy, his or her: (1) Ancestor or descendant by blood or adoption; or (2) Stepchild, while the marriage creating that relationship exists; or (3) Brother or sister of the whole or half-blood; or (4) Uncle, aunt, nephew or niece of the whole blood. 2. The offense of incest is a class E felony. 3. The court shall not grant probation to a person who has previously been found guilty of an offense under this section. § 568.020, RSMo Amended by 2014 Mo. Laws, SB 491,s A, eff. 1/1/2017. L. 1977 S.B. 60, A.L. 1979 S.B. 234, A.L. 2006H.B. 1698 , et al. Effective 6-05-06