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 Indiana, the criminal offense of sexual assault of a child is addressed under the state's criminal statutes concerning sex crimes against children, which include child molestation, child exploitation, and child seduction among others. Specifically, Indiana Code Title 35, Article 42, Chapter 4 outlines various sex offenses, where acts described in the query would generally fall under child molestation (IC 35-42-4-3). This statute makes it a felony for any person to perform or submit to any sexual act with a child under the age of 14, regardless of whether the perpetrator knew the age of the child at the time of the offense. The law covers a range of conduct, including any sexual intercourse, deviate sexual conduct (which includes oral and anal sex), or any touching with the intent to arouse or satisfy the sexual desires of either the child or the person. Penalties for these offenses are severe and can include significant prison time, with the exact sentence depending on the nature of the act and the age of the child.