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 Nevada, sexual assault of a child is a serious criminal offense, and the state's laws reflect this gravity. Under Nevada Revised Statutes (NRS) 200.366, a person commits sexual assault by subjecting another person to sexual penetration against their will or under conditions in which the perpetrator knows or should know that the victim is mentally or physically incapable of resisting or understanding the nature of their conduct. When the victim is a child under the age of 16, the offense is considered more severe, and the perpetrator's knowledge of the child's age is not a defense. The law covers various acts of sexual penetration, including any contact between the genitals of one person and the mouth or anus of another person, as well as penetration of the sexual organ or anus of a child by any object. Conviction for sexual assault of a child in Nevada can result in severe penalties, including life imprisonment, with or without the possibility of parole, depending on the specific circumstances and whether the offender has prior convictions for similar offenses.