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 Oregon, incest is defined under ORS 163.525 and is considered a criminal offense. The law prohibits sexual relations or marriage between close relatives, including ancestors and descendants by blood or adoption, stepchildren and stepparents, siblings of whole or half blood or by adoption, and nieces, nephews, aunts, and uncles of whole or half blood or by adoption. Consent is not a defense to the crime of incest in Oregon, meaning that the offense can be prosecuted even if both parties consented to the sexual relationship. Incest is classified as a Class C felony in Oregon, which can result in significant penalties, including potential imprisonment, fines, and a criminal record.