Kentucky Incest Law: Penalties, Registration, and Defenses

Kentucky incest law, codified at KRS 530.020, makes sexual intercourse or deviate sexual intercourse with a covered relative a felony punishable by five to twenty years in prison, requires lifetime sex offender registration on conviction, and voids any marriage between people closer in blood than second cousins. The list of covered relatives reaches well past parents, children, and siblings.

Who Counts as a Relative

KRS 530.020 applies when a person knows the other individual is a covered relative. That knowledge element matters: an accidental encounter between relatives who genuinely had no idea they were related is not the same offense, though proving the absence of knowledge is difficult in practice.

The prohibited relationships are:

Direct ancestors and descendants: parents, children, grandparents, grandchildren, great-grandparents, and great-grandchildren
Brothers and sisters, whether full or half-blood
Uncles, aunts, nephews, nieces, and first cousins
Adoptive parents and children, stepparents and stepchildren, and stepgrandparents and stepgrandchildren

Blood relationships count regardless of whether the individuals were born within a marriage.¹

Prison Time by Class

The offense splits into two felony classes based on the circumstances of the act, not simply the ages of the people involved.

Class C Felony: Consenting Adults

When both parties are consenting adults, incest is a Class C felony punishable by five to ten years in prison.¹² Agreement between the parties does not remove the criminality; it only lowers the sentencing range.

Class B Felony: Aggravating Circumstances

The offense becomes a Class B felony carrying ten to twenty years in prison when any of these conditions apply:

The other person did not consent
The offender used forcible compulsion (physical force or threats)
The other person was under eighteen and the offender was at least three years older
The other person was physically helpless or mentally incapacitated

The three-year age gap means a nineteen-year-old and a seventeen-year-old cousin fall under the Class B provision, while two seventeen-year-old siblings would be charged under Class C.¹²

Sex Offender Registration

A conviction under KRS 530.020 triggers mandatory registration. KRS 17.500 classifies incest as a “sex crime,” and anyone convicted of a sex crime is designated a “sexual offender” who must register.³ Registration limits where the person can live and work, and the person’s information becomes accessible to the public. For many convicted individuals, the registration requirements shape daily life longer than the prison sentence itself.

Consent Does Not Defeat the Charge

A common misunderstanding is that mutual agreement makes the conduct legal. It does not. Consent affects only whether the offense is charged as a Class C or Class B felony. And there is no marital exception: being married to the other person, even if the marriage was performed in another state, does not create a defense, because Kentucky treats such marriages as void from their inception.

Marriage Between Relatives Is Void

KRS 402.010 bars marriage between anyone closer in blood than second cousins, whole or half blood. Any such marriage is automatically void, meaning it has no legal effect from the moment it occurs and does not need a court order to dissolve.⁴ Second cousins themselves may legally marry.

Available Defenses

Realistic defenses are narrow and typically challenge the prosecution’s proof rather than the statute itself.

Lack of knowledge. Because the statute requires that the defendant knew the other person was a covered relative, a genuine unawareness of the family connection is a defense. This most often arises with relatives separated at birth or raised in different families.
Identity. When DNA or other physical evidence is unavailable or contested, the defense may argue the prosecution cannot prove the defendant was the person involved.
Procedural challenges. How evidence was collected, whether search warrants were valid, and whether investigators followed constitutional requirements during interrogation are all fair targets.

Civil Claims by Victims

A criminal case is not the only avenue. Victims can sue their abusers for compensatory damages covering therapy costs, lost wages, and emotional harm, and punitive damages may also be available.

KRS 413.249 gives childhood sexual abuse victims a ten-year window that begins when the victim turns eighteen, so a claim can be filed up to age twenty-eight. For victims whose claims had already expired before March 23, 2021, the legislature created a revival window allowing those claims to be filed within five years of the date the original deadline passed.⁵

Immigration Consequences

For non-citizens, the fallout can equal the prison sentence. The U.S. Department of State classifies incest resulting from a sexual relationship as a crime involving moral turpitude, which can make a person ineligible for a visa and subject to deportation.⁶ A lawful permanent resident convicted of incest in Kentucky faces potential removal proceedings on top of the state penalties.

Duty to Report Suspected Abuse

Kentucky requires anyone with reasonable cause to believe a child is being abused, neglected, or victimized by incest to report it immediately. The duty applies to everyone, not only professionals such as teachers, doctors, and social workers. Reports can be made to local law enforcement, the Kentucky State Police, the cabinet or its designated representative, the Commonwealth’s attorney, or the county attorney, and may be oral, written, or electronic.⁷

Intentionally failing to report is a Class B misdemeanor on the first offense, a Class A misdemeanor on the second, and a Class D felony punishable by one to five years in prison on a third or subsequent offense.⁷ Anyone who makes a good-faith report is immune from civil and criminal liability under KRS 620.050, and that immunity extends to participation in any resulting judicial proceeding. The immunity disappears only if someone knowingly files a false report with malice, which is itself a Class A misdemeanor.⁸

1
Kentucky Legislative Research Commission. Kentucky Code 530.020 – Incest
2
Justia Law. Kentucky Revised Statutes 532.060 – Sentence of Imprisonment for Felony – Postincarceration Supervision
3
Kentucky Legislative Research Commission. Kentucky Code 17.500 – Definitions for KRS 17.500 to 17.580
4
Kentucky Legislative Research Commission. Kentucky Code 402.010 – Degree of Relationship That Will Bar Marriage
5
Kentucky Legislative Research Commission. Kentucky Code 413.249 – Action Relating to Childhood Sexual Abuse
6
U.S. Department of State. Foreign Affairs Manual – Ineligibility Based on Criminal Activity – Crimes Involving Moral Turpitude
7
Kentucky Legislative Research Commission. Kentucky Code 620.030 – Duty to Report Dependency, Neglect, Abuse, Human Trafficking, or Female Genital Mutilation
8
Kentucky Legislative Research Commission. Kentucky Code 620.050 – Immunity for Good-Faith Reporting