Is It a Crime to Transmit an STD in California?

The basics of California's criminal laws on STD transmission, exposure, and disclosures.

By , Attorney

The state of California has several criminal laws that address transmitting sexually transmitted diseases (STDs) or exposing others to the danger of transmission.

Is It Illegal to Transmit or Expose Someone to a Sexually Transmitted Disease (STD) in California?

Yes, it can be. Generally speaking, California makes it a misdemeanor to intentionally transmit or willfully expose another person to a venereal disease or an infectious or communicable disease, which includes STDs and HIV. We review these crimes in more detail below.

STDs and venereal diseases include:

  • chlamydia
  • gonorrhea
  • herpes
  • hepatitis B
  • human immunodeficiency virus (HIV)
  • human papillomavirus (HPV)
  • lymphogranuloma venereum (LGV)
  • mycoplasma genitalium (MGen)
  • pelvic inflammatory disease (PID)
  • syphilis, and
  • trichomoniasis.

(Under a previous version of the law, California made it a felony to intentionally transmit HIV. But this crime and several related crimes were eliminated in 2017.)

California's Laws on Intentional Transmission of an STD

Defendants who intentionally transmit STDs can face misdemeanor criminal charges if it's shown a defendant:

  • knew they had an STD
  • intended to transmit the STD to another person
  • did not inform the person of their infected status
  • engaged in conduct that greatly risked transmission, and
  • transmitted the STD to the other person.

Third-party transmission. A person can also be convicted of this offense if they caused transmission through a third party. For instance, say a defendant knows that a friend has an STD and convinces the friend to have sex with the defendant's ex-spouse. The defendant (and the friend) could be convicted under this section.

Defense. A defendant who knows they have an STD but took measures to prevent transmission (such as by wearing a condom) doesn't commit a crime under this section.

California's Laws on Willful Exposure of an STD

If no transmission results, a prosecutor could still charge the offense under California's willful exposure law. A person commits a misdemeanor under this section by ignoring a health official's instructions not to engage in conduct that poses a substantial risk of transmission. For a conviction under this section, the offense (willful exposure of an STD) must take place within 96 hours of receiving the instruction.

California's Laws on Exposure or Infection of a Venereal Disease

California has another statute that makes it a crime to expose or transmit a venereal disease to another. This crime applies specifically to syphilis, gonorrhea, chlamydia, and LGV. Under this section, a defendant who exposes or infects a person with a venereal disease commits a misdemeanor. It's also a misdemeanor for defendants who know they have a venereal disease and are infectious to marry or have sexual intercourse with another person.

What Are the Penalties for Giving Someone an STD in California?

A conviction for intentionally giving someone, or exposing them to, an STD or venereal disease carries a misdemeanor sentence of up to six months in jail and a $1,000 fine. Attempting to transmit an STD can result in a 90-day jail sentence.

Defendants who commit certain sexual offenses (like rape) knowing they are infected with HIV or have AIDS will face mandatory sentencing enhancements. The judge must add three years to the defendant's sentence.

What Are California's STD Disclosure Laws?

California law doesn't specifically require a person to disclose an STD to a former or current sexual partner. But the decision not to tell a current sexual partner can result in the criminal charges above. If you know you have an STD and engage in sex without telling your partner, you could be convicted of intentional transmission, attempted transmission, or willful exposure of an STD. Informing your partner is a defense to these charges.

And, for likely obvious reasons, it's a good idea to inform your current or past partners so they can make informed decisions, and if needed, get tested and treated right away. The platform offers individuals an anonymous way to inform their partners, as well as other resources to stop the spread of STDs.

Defenses for STD-Related Crimes

To be convicted of an STD crime, defendants generally must know they have the disease and intend for the other person to get it. If a defendant didn't know they had an STD, there's no crime. Even if the defendant knew they were infected, the prosecutor must still show the defendant intended for the other person to get the STD or willfully exposed them to it. A defendant who's been told the risk of transmission is low might be able to argue they lacked the required intent or that they didn't engage in substantially risky behavior. As noted above, it's also a defense to intentional transmission of an STD if a defendant took measures to prevent transmission or informed their partner of their infected status.

Talk to a Lawyer

If you're facing criminal charges, talk to a local criminal defense attorney. A defense attorney can help you understand the charges and their potential penalties, navigate the criminal legal system, and evaluate possible defenses.

(Cal. Health & Safety Code §§ 120130, 120290, 120500, 120600; Cal. Penal Code § 12022.85 (2022).)

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