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 Pennsylvania, the criminal offense of sexual assault of a child is taken very seriously and is addressed under the state's penal code. The offenses described, involving various forms of sexual penetration or contact with a child, would generally fall under the categories of statutory sexual assault, involuntary deviate sexual intercourse, and other related offenses such as aggravated indecent assault. Pennsylvania law defines a child as an individual under the age of 16, and the state does not require the perpetrator to have knowledge of the child's age to be charged with these offenses. The severity of the charges and the associated penalties can vary based on factors such as the ages of the individuals involved, the nature of the acts, and the presence of force or coercion. Convictions for these crimes can result in significant prison time, fines, and mandatory registration as a sex offender under Pennsylvania's Megan's Law.