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 Arizona, the criminal offense of sexual assault of a child is a serious crime and is addressed under Arizona's sexual conduct with a minor statutes. According to Arizona Revised Statutes §13-1405, a person commits sexual conduct with a minor by intentionally or knowingly engaging in sexual intercourse or oral sexual contact with any person who is under eighteen years of age. The severity of the offense and the associated penalties can vary based on the age of the victim and the age difference between the victim and the defendant. For instance, if the victim is under 15 years of age, the offense is classified as a class 2 felony and is considered a dangerous crime against children. In Arizona, the law does not require that the defendant knew the age of the child at the time of the offense for them to be charged and convicted. The statutes are designed to protect minors from sexual exploitation and abuse, and the state imposes strict penalties on those found guilty of such offenses.