Yes, incest is illegal in California. Under Penal Code 285, sexual intercourse or marriage between close blood relatives is a felony punishable by 16 months, two years, or three years in state prison, and a conviction requires the defendant to register as a sex offender.1California Legislative Information. California Penal Code 285 Consent is not a defense, and both adults involved can be charged.
Which Relationships the Law Covers
Penal Code 285 doesn’t list family members itself. It borrows its definitions from Family Code 2200, which identifies the relationships that make a marriage “incestuous and void.” Those are:
- Parents and children
- Grandparents, great-grandparents, and any ancestor or descendant, no matter how many generations apart
- Siblings, including half-siblings
- Uncles or aunts with nieces or nephews
Family Code 2200 applies these rules “whether the relationship is legitimate or illegitimate,” so a child born outside marriage is still covered.2California Legislative Information. California Family Code 2200
Relationships That Are Not Covered
The statute uses the word “consanguinity,” meaning blood relation. Several relationships people often assume fall under the incest statute actually do not. First cousins, stepparents and stepchildren, stepsiblings, and adopted siblings are all excluded from PC 285.1California Legislative Information. California Penal Code 285 Other states draw the line differently. California draws it at shared blood.
Marriage and Sexual Acts Both Count
PC 285 punishes two separate acts: marrying a prohibited relative, and committing “fornication or adultery” with one. A couple doesn’t have to be married for the law to reach them. Any sexual intercourse between people in the prohibited relationships triggers criminal liability.
Consent Is Not a Defense
Unlike most sex crimes, incest doesn’t turn on whether one person was unwilling. Both participants can be prosecuted. The statute treats the act itself as the offense regardless of whether it was mutual, which is what separates PC 285 from crimes like rape, where the focus is on lack of consent.
When One Person Is Under 14
PC 285 applies only when both people are at least 14 years old. That doesn’t mean conduct with a younger child goes unpunished. Prosecutors file more serious charges instead, carrying significantly longer prison sentences than incest itself.1California Legislative Information. California Penal Code 285
Prison, Fines, and Restitution
Incest is a straight felony. There is no misdemeanor version. Because PC 285 is a registerable sex offense, the sentence is served in state prison rather than county jail, and the term is 16 months, two years, or three years under California’s standard felony triad.1California Legislative Information. California Penal Code 285
PC 285 itself doesn’t set a fine amount, but Penal Code 672 lets a judge impose up to $10,000 on any felony where the underlying statute is silent. The fine is discretionary.3California Legislative Information. California Penal Code 672
Restitution is separate. Under Penal Code 1202.4, courts must order restitution to victims for economic losses in nearly every conviction. Covered costs can include therapy, medical bills, lost income, relocation, and residential security upgrades.4California Legislative Information. California Penal Code 1202.4 In cases involving long-running abuse, therapy costs alone can be substantial.
Mandatory Sex Offender Registration
A PC 285 conviction triggers mandatory registration under Penal Code 290. For most people, this is the consequence that outlasts everything else. Under California’s tiered system, registrants are assigned to one of three tiers: 10 years, 20 years, or lifetime.5California Legislative Information. California Penal Code 290 The tier controls how long you have to report your address, comply with registration conditions, and potentially appear on the public Megan’s Law website. It also shapes where you can live and work.
Other Consequences of a Felony Conviction
The formal sentence is only part of what a conviction changes.
Firearms
Federal law under 18 U.S.C. 922(g)(1) bars anyone with a felony conviction from possessing a firearm. California imposes its own parallel ban. A PC 285 conviction ends gun rights unless the conviction is later expunged or reduced in a way that lifts the federal disability.
Immigration
For noncitizens, an incest conviction can lead to deportation or inadmissibility. The State Department’s Foreign Affairs Manual treats incest as a crime that may involve moral turpitude when it arises from a sexual relationship rather than purely from a prohibited marital status. That finding renders an immigrant visa applicant ineligible under INA 212(a)(2)(A)(i)(I), though limited waivers exist.6U.S. Department of State. Foreign Affairs Manual – Ineligibility Based on Criminal Activity
Custody and Parental Rights
A sex offense conviction weighs heavily in any custody or visitation decision. Outcomes range from supervised visitation to full termination of parental rights, depending on whether the child was involved and the circumstances of the case. Regaining custody afterward typically requires years of demonstrated rehabilitation.
Defenses That May Apply
Because the prosecution has to prove both a qualifying blood relationship and a sexual act, defenses generally attack one of those elements.
Not Knowing About the Relationship
This defense 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 are related have a real factual basis for arguing they lacked the mental state the offense requires. The defendant has to show the ignorance was genuine rather than willful.
Duress or Coercion
If one party was forced or threatened into the act, duress can serve as a defense. This matters most where there was a power imbalance inside the family. Proving it usually requires evidence of a credible, immediate threat that left no reasonable alternative.
What Won’t Work
Consent is not a defense. Neither is the argument that both parties were adults, that the relationship caused no harm, or that no children could result. None of those points negate any element of PC 285.