It is an all encompassing law which includes both boys and girls I would assume.
I had an occasion to listen to people engage leisurely on the topic and figured just how misunderstood and confusing the offence of defilement is to people vis-à-vis the offence of rape. It is important to note that the point of departure on the two offences is that with regards rape, the law suggests that the perpetrator must have sought sexual gratification of another without their consent. As regards defilement, the perpetrator must have had sexual intercourse with a person below the age of 16.