Incest Laws

Almost all states prohibit consensual sexual conduct between close relatives. Justifications for these laws include protecting the stability of a family and avoiding the genetic defects that are more likely to arise in offspring of these relationships. Incest also may be linked to child sexual abuse, although states punish that offense separately. A person who thinks that they may be suspected of incest should not tell their side of the story to the police directly. Instead, they should enlist an attorney who can develop a strategy to avoid or minimize any consequences.

What Is Incest?

Incest generally involves sexual activity between certain family members, although sometimes marriage or cohabitation is enough.

Elements of Incest

A prosecutor seeking a conviction for incest will need to prove that the defendant engaged in certain conduct prohibited by the applicable statute. Some states, such as Georgia and Illinois, require sexual intercourse or penetration. Other states, such as Michigan and Washington, prohibit a broader range of sexual conduct. In states such as California and Florida, a prosecutor can get a conviction simply by proving marriage, even if no sex occurred. In Pennsylvania and a handful of other states, “cohabitation” is enough without a formal marriage.

In addition, a prosecutor must show that a certain family relationship existed between the parties. For example, Colorado Revised Statutes Section 18-6-301 covers ancestors or descendants, including natural children, adopted children, and stepchildren who are 21 or older, as well as brothers and sisters, half-brothers and half-sisters, uncles and aunts, and nephews and nieces. Michigan Compiled Laws Section 750.520e covers people related by blood or affinity to the third degree. Some statutes, such as those in California and Massachusetts, simply make sexual conduct illegal between people for whom marriage would be illegal.

A prosecutor also may need to prove that the defendant knew about the family relationship. This may be obvious in some cases, but others may be less clear.

Examples of Incest

Peter consoles his niece Penelope after her boyfriend dumps her. Penelope tells Peter that she would feel better if he had sex with her. If Peter agrees, this likely would be incest.

Paul’s father has an affair that produces a daughter called Patricia. Paul and Patricia eventually attend the same college, where they find out that they share the same dad. After a party, Patricia gives Paul a blowjob. This would be incest in some states, such as New York.

Offenses Related to Incest

Some crimes that could be charged in situations similar to those supporting an incest charge include:

• Rape: non-consensual sex
• Statutory rape: sex with a person who is too young to consent
• Sexual assault: various non-consensual sexual acts
• Indecent exposure: intentionally displaying genitals or other private parts in public or in another setting where it causes offense
• Child molestation: sexual touching, fondling, or other improper acts targeting a child

A defendant sometimes may face multiple charges varying in severity. If they do not have a strong defense to all the charges, they might consider pleading guilty to a lesser charge while getting a greater charge dismissed.

Defenses to Incest

Sometimes a defendant might argue that they did not engage in the conduct specified by the statute. For example, perhaps they briefly dated their stepsister but did not go beyond some sexual touching. This would not constitute incest in a state that requires intercourse or penetration. In other cases, a defendant might argue that they did not know about the family relationship. While this would not preserve a marriage with their relative, it could potentially defeat a criminal charge.

Another strategy might involve questioning the credibility of prosecution witnesses. Perhaps the person accusing the defendant of having sex with a family member has a motive to lie, such as a grudge against the defendant. Or perhaps the accuser innocently misinterpreted an incident or conversation. A woman who makes a stray comment about the penis of her father, for example, might have seen his penis accidentally and not have had sex with him.

Penalties for Incest

Incest may seem less serious than some sex crimes, due to the consensual nature of the conduct. However, it may lead to years in prison. Here is a selection of potential prison terms in various states:

• Arizona: 1.5-3 years (2.5 years presumptive)
• Florida: up to 5 years
• Illinois: 2-5 years
• Massachusetts: up to 20 years in state prison, or up to 2.5 years in house of correction
• Missouri: up to 4 years
• Pennsylvania: up to 10 years
• Texas: generally 2-10 years (2-20 years if committed with ancestor or descendant by blood or adoption)
• Washington: up to 10 years (if sexual intercourse); up to 5 years (if sexual contact)

Some states, such as California, also require a person convicted of incest to register as a sex offender. More generally, having this type of conviction on record could pose challenges to a defendant in achieving key personal and professional goals.

Last reviewed August 2024