A person generally commits the criminal offense of sexual assault of a child—regardless of whether the person knows the age of the child at the time of the offense—if the person (1) causes the penetration of the anus or sexual organ of a child by any means; (2) causes the penetration of the mouth of a child by the sexual organ of the person; (3) causes the sexual organ of the child to contact or penetrate the mouth, anus, or sexual organ of the person or another person; (4) causes the anus of a child to contact the mouth, anus, or sexual organ of the person or another person; or (5) causes the mouth of a child to contact the anus or sexual organ of the person or another person.

The naming and definition of the criminal offense of sexual assault of a child varies from state to state. These criminal offenses are generally located in a state’s statutes—often in the penal or criminal code.

In South Carolina, the criminal offense of sexual assault of a child is addressed under the state's sexual battery laws. Sexual battery is defined as sexual intercourse, cunnilingus, fellatio, anal intercourse, or any intrusion, however slight, of any part of a person's body or of any object into the genital or anal openings of another person's body, except when performed for medically recognized treatment or diagnostic purposes. When the victim is a child under the age of 16, and the perpetrator is over a certain age (usually 18 or older), the offense is considered criminal sexual conduct with a minor. South Carolina law does not require the perpetrator to know the age of the child for the act to be considered a criminal offense. The severity of the charge (first, second, or third degree) and the associated penalties vary based on factors such as the ages of the perpetrator and the victim, the nature of the act, and whether force or coercion was used. These laws are codified in the South Carolina Code of Laws, particularly in Title 16 - Crimes and Offenses, Chapter 3 - Offenses Against the Person.