Any sexual activity between an adult or adolescent and a child is child sexual abuse. It is not just harmful to children: it is against the law.  According to the American Professional Society on the Abuse of Children (APSAC) in its Handbook on Child Maltreatment (2nd Edition, 2002):

“Child sexual abuse involves any sexual activity with a child where consent is not or cannot be given. This includes sexual contact that is accomplished by force or threat of force, regardless of the age of the participants, and all sexual contact between an adult and a child, regardless of whether there is deception or the child understands the sexual nature of the activity. Sexual contact between an older and a younger child also can be abusive if there is a significant disparity in age, development, or size, rendering the younger child incapable of giving informed consent.”

Child sexual abuse can include both touching and non-touching behaviors and its victims can include infants, toddlers, young childrens, and teens:

Examples of abusive touching behaviors include: fondling of a child’s genitals, buttocks or breasts; intercourse; and, penetration of the child’s mouth, anus, or vagina with an object for the sexual gratification of the offender. Coercing a child to fondle him/herself, the offender or another child is also abusive.

Examples of abusive non-touching behaviors include: exposing oneself to a child; viewing and violating the private behaviors of a child or teen (e.g. while undressing, bathing, etc); taking sexually explicit or provocative photographs of a child; and showing pornography to a child.