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 Maine, the criminal offense of sexual assault of a child is addressed under the state's statutes concerning sexual offenses. Specifically, these acts would fall under the category of 'Gross Sexual Assault' as defined in Title 17-A, Section 253 of the Maine Criminal Code. The law states that a person is guilty of gross sexual assault if they engage in a sexual act with another person and the other person has not attained 14 years of age (among other conditions). The statute does not require the perpetrator to have knowledge of the child's age to be held liable. Gross sexual assault is a serious crime in Maine and is classified as a Class A, B, or C crime, depending on the circumstances, with Class A being the most serious. Penalties for these offenses can include significant prison time and other legal consequences. It is important to note that Maine law also includes provisions for 'Unlawful Sexual Contact' and 'Sexual Abuse of Minors' under Sections 255-A and 254, respectively, which cover a broader range of sexual offenses against children.