Yes, incest is illegal in California. Under Penal Code 285, both marriage and sexual intercourse between close blood relatives are a felony, punishable by 16 months, two years, or three years in state prison, with mandatory sex offender registration on top.1California Legislative Information. California Penal Code 285 Consent is not a defense, and both participants can be charged.
Which Relationships the Law Covers
PC 285 does not list family members itself. It borrows the definition from California Family Code 2200, which identifies the relationships that make a marriage “incestuous and void”:
- Parents and children
- Grandparents, great-grandparents, and any ancestor or descendant, no matter how many generations apart
- Siblings, including half-siblings
- Uncles or aunts and nieces or nephews
Family Code 2200 applies “whether the relationship is legitimate or illegitimate,” so a child born outside marriage is still covered.2California Legislative Information. California Family Code 2200
Who Is Not Covered
The statute turns on consanguinity, meaning a blood relation. Several pairings people assume are illegal fall outside PC 285: first cousins, stepparents and stepchildren, stepsiblings, and adopted siblings.1California Legislative Information. California Penal Code 285 Other states treat some of these differently, but California draws the line at shared blood.
What Acts Are Prohibited
PC 285 reaches two kinds of conduct: intermarrying with a prohibited relative, and committing “fornication or adultery” with one. Marriage is not required. Any sexual intercourse between people in the listed relationships triggers criminal liability.1California Legislative Information. California Penal Code 285
Unlike most sex crimes, consent is not an element. Both participants can be prosecuted, because the law treats the act itself as the offense regardless of whether it was mutual.
The Age 14 Threshold
PC 285 applies only when both people are at least 14. When a relative under 14 is involved, prosecutors generally file heavier charges instead, such as lewd acts on a child under 14 (PC 288) or continuous sexual abuse of a child (PC 288.5). Those offenses carry significantly longer prison sentences than PC 285.1California Legislative Information. California Penal Code 285
Penalties for a Conviction
Incest is a straight felony. There is no misdemeanor version. The sentence follows California’s standard felony triad of 16 months, two years, or three years in state prison. Because PC 285 is a registerable sex offense, it does not qualify for county jail time under PC 1170(h); the time is served in state prison.1California Legislative Information. California Penal Code 285
PC 285 sets no specific fine, but Penal Code 672 authorizes a judge to impose up to $10,000 on any felony where the underlying statute is silent on fines. That amount is discretionary.3California Legislative Information. California Penal Code 672 Separately, Penal Code 1202.4 requires courts to order victim restitution for economic losses, which in incest cases can include therapy, medical costs, lost income, relocation, and residential security.4California Legislative Information. California Penal Code 1202.4
Sex Offender Registration
A PC 285 conviction triggers mandatory registration under Penal Code 290. Under the tiered system adopted through SB 384, registrants are placed in one of three tiers lasting 10 years, 20 years, or life, depending on the offense. Registration governs where you can live, where you can work, and whether your information appears on the public Megan’s Law website.5California Legislative Information. California Penal Code 290 For many people convicted under PC 285, this is the consequence that outlasts everything else.
Other Consequences Beyond the Sentence
A felony incest conviction reaches into areas judges often do not spell out at sentencing.
Firearm Rights
Federal law under 18 U.S.C. 922(g)(1) bars anyone convicted of a felony from possessing a firearm, and California imposes its own parallel ban. A PC 285 conviction permanently strips gun rights unless the conviction is later expunged or reduced in a way that removes the disability.
Immigration
For noncitizens, incest can trigger deportation or inadmissibility. The State Department’s Foreign Affairs Manual lists incest as a crime that may involve moral turpitude when it arises from a sexual relationship rather than a prohibited marital status alone, which makes an immigrant visa applicant ineligible under INA 212(a)(2)(A)(i)(I). Limited waivers exist, including for offenses more than 15 years old with proof of rehabilitation.6U.S. Department of State. Foreign Affairs Manual – Ineligibility Based on Criminal Activity
Custody and Parental Rights
Family courts weighing the best interests of a child treat a sex offense conviction as a major factor. Outcomes can range from supervised visitation to full termination of parental rights, depending on whether the child was a victim and the broader circumstances. Regaining custody after a conviction typically takes years of documented rehabilitation.
Defenses That Can Work
Because the prosecution has to prove both a qualifying family relationship and a sexual act, viable defenses usually attack one or the other.
Not Knowing About the Relationship
This comes up most often in adoption and donor-conception situations. Siblings separated at birth who meet as adults and start a relationship without knowing they share a parent have a factual basis for arguing they lacked the mental state the offense requires. The ignorance has to be genuine, not willful.
Duress or Coercion
If one party was forced or threatened into the sexual act, duress can be raised. It matters most where there is a serious power imbalance inside the family. Proving it generally requires a credible threat of immediate harm that left no reasonable alternative.
What Does Not Work
Consent is not a defense. Mutual willingness between adults does not negate the offense, because the statute criminalizes the act itself between prohibited relatives. Arguments that the relationship caused no harm, or that no children could result, do not defeat the elements either.