This chapter describes what the current literature tells us about child sexual abuse and childhood sexual experiences. It estimates how many people have childhood sexual experiences with adults and their potential impact on the person. The chapter identifies the extent to which the family and environmental factors can be protective and risk factors. It examines the prevalence of child sexual abuse and its long-term effects, and the protective and risk factors including the family environment and other influences such as cultural differences. The chapter focuses on the experiences of adults who were sexually abused in childhood, rather than on the experiences of families in which a child has recently disclosed sexual abuse, or on victimisers. It presents a more balanced picture of the range of possible outcomes following childhood sexual experiences with adults.