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 Idaho, incest is defined as sexual relations or marriage between close relatives, and it is considered a felony offense under Idaho Code § 18-6602. The law specifically prohibits sexual relations or marriage between ancestors and descendants, including those by adoption, between siblings of the whole or half blood, including those by adoption, and between uncles, aunts, nephews, and nieces. This prohibition extends to stepchildren and stepparents as well. Consent is not a defense to the charge of incest in Idaho, meaning that the crime can be prosecuted even if both parties consented to the sexual relationship. Those convicted of incest in Idaho face potential penalties including imprisonment and fines. It is important for individuals in Idaho to be aware of these regulations to avoid legal repercussions related to incestuous conduct.