The transmission of a sexually transmitted disease (STD) from a person who knows or should know they have the disease to another person who is not informed of that fact before engaging in sexual contact with the infected person may result in both civil liability (for money damages) and criminal liability (for penalties).

Laws vary from state to state and some states have both civil and criminal statutes (laws enacted by the state legislature) that specifically address the transmission of sexually transmitted diseases. In other states civil lawsuits may be filed and criminal prosecutions may be made under traditional legal theories such as negligence in a civil lawsuit and battery (harmful or offensive physical contact without consent) in a criminal prosecution.

In Washington State, the transmission of a sexually transmitted disease (STD) by an individual who knows or should know they are infected to an uninformed partner can lead to both civil and criminal consequences. Under Washington law, RCW 70.24.080 specifically addresses the issue, making it unlawful for a person with an STD to engage in conduct that is likely to transmit the disease to someone else. This can include sexual activity without informing the partner of the STD. Civil liability may arise under claims of negligence or battery, where the infected person had a duty to inform their partner and failed to do so, resulting in harm. Criminal liability can also occur, with potential charges ranging from misdemeanor to felony, depending on the circumstances and the STD involved. It is important for individuals to be aware of their health status and to communicate openly with sexual partners to avoid legal repercussions.