Incest is marriage or sexual relations between close relatives. The criminal offense of incest may also be known as prohibited sexual conduct. Laws vary from state to state, but incest laws generally prohibit marriage or sexual relations between (1) a person’s ancestor or descendant by blood or adoption; (2) a person’s current or former stepchild or stepparent; (3) a person’s parent’s brother or sister of the whole or half blood; (4) a person’s brother or sister of the whole or half blood or by adoption; (5) the children of a person’s brother or sister of the whole or half blood, or by adoption; or (6) the son or daughter of a person’s aunt or uncle of the whole or half blood or by adoption.

Lack of consent to sexual relations between such relatives is not an element of the crime, and persons may be guilty of the crime even if both parties consented.

Laws regarding incest or prohibited sexual contact vary from state to state and are generally located in a state’s statutes—often in the penal or criminal code. The crime is a felony offense in many states, with potential punishment of significant jail or prison time.

In Kansas, incest is defined as engaging in sexual intercourse or sodomy with a person who is known to be a relative, either biologically or through marriage. Specifically, Kansas law prohibits such relations between a person and their parent, grandparent, child, grandchild, sibling, half-sibling, aunt, uncle, niece, or nephew. This prohibition extends to both blood relatives and those related by marriage or adoption. Incest is considered a severe offense in Kansas and is classified as a level 10 felony under the Kansas Statutes Annotated (K.S.A. 21-5604). The fact that both parties consent to the sexual relationship does not serve as a defense in cases of incest, meaning that consent is not a relevant factor in determining guilt under this statute. Conviction of incest in Kansas can result in substantial penalties, including imprisonment and fines.