If the victim is less than 15 (all ages up to the day she turns 15) and the perpetrator is at least four years older and is not her spouse, it is statutory rape.  If the victim is 15 to just under 17, and the perpetrator is at least 10 years older and is not her spouse, it is statutory rape.  Anyone who knowingly subjects another who is not his spouse to any sexual contact, commits "sexual assault on a child" if the victim is under 15 and the perpetrator is at least 4 years older.