The effects of child sexual abuse include depression, post-traumatic stress disorder, anxiety, propensity to re-victimization in adulthood, and physical injury to the child, among other problems.[9] Sexual abuse by a family member is a form of incest, and can result in more serious and long-term psychological trauma, especially in the case of parental incest.

Approximately 15% to 25% of women and 5% to 15% of men were sexually abused when they were children. Most sexual abuse offenders are acquainted with their victims; approximately 30% are relatives of the child, most often brothers, fathers, uncles or cousins; around 60% are other acquaintances such as friends of the family, babysitters, or neighbors; strangers are the offenders in approximately 10% of child sexual abuse cases. Most child sexual abuse is committed by men; studies show that women commit 14% to 40% of offenses reported against boys and 6% of offenses reported against girls. Most offenders who abuse pre-pubescent children are pedophiles, however a small percentage do not meet the diagnostic criteria for pedophilia.

Under the law, "child sexual abuse" is an umbrella term describing criminal and civil offenses in which an adult engages in sexual activity with a minor or exploits a minor for the purpose of sexual gratification. The American Psychiatric Association states that "children cannot consent to sexual activity with adults", and condemns any such action by an adult: "An adult who engages in sexual activity with a child is performing a criminal and immoral act which never can be considered normal or socially acceptable behavior.

Child sexual abuse includes a variety of sexual offenses, including:

• Sexual Assault – a term defining offenses in which an adult touches a minor for the purpose of sexual gratification; for example, rape (including sodomy), and sexual penetration with an object. Most U.S. states include, in their definitions of sexual assault, any penetrative contact of a minor’s body, however slight, if the contact is performed for the purpose of sexual gratification.
• Sexual Molestation – a term defining offenses in which an adult engages in non-penetrative activity with a minor for the purpose of sexual gratification; for example, exposing a minor to pornography or to the sexual acts of others.
• Sexual Exploitation – a term defining offenses in which an adult victimizes a minor for advancement, sexual gratification, or profit; for example, prostituting a child, and creating or trafficking in child pornography.
• Sexual Grooming - defines the social conduct of a potential child sex offender who seeks to make a minor more accepting of their advances, for example in an online chat room.