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 Oklahoma, incest is defined under state law as marriage or sexual intercourse between persons who are within degrees of consanguinity that makes marriage incestuous and void. This includes ancestors, descendants, aunts, uncles, nieces, nephews, siblings, or half-siblings, whether related by blood or adoption. Oklahoma law specifically prohibits marriage between such relatives and deems it incestuous and void from the beginning. Additionally, engaging in sexual intercourse with a close relative as defined by the law is a felony offense. Consent is not a defense to a charge of incest, meaning that the crime can be prosecuted even if both parties consented to the sexual relationship. Those convicted of incest in Oklahoma may face penalties including imprisonment, and the severity of the punishment can vary depending on the specific circumstances of the offense.