Several studies have supported traditional incest taboos by showing that children born from incestuous unions are more likely to exhibit poor health, physical defects, and mental retardation than outbred offspring. While some writers have stated that child victims of sexual abuse suffer irreparable damage and are prone to delinquency, it must be noted that professional and middle-class social groups are probably not included in any data on which these theories are based. Other researchers have contended that a child's emotional state will not be impaired by a sexual attack if the family environment is stable and supportive. According to a survey of 263 sexually abused children in New York City, the effect on the child may be greater if there is an element of attack or if the child is disgraced, punished, or forced to testify publicly. A close relationship between the offender and the child increases the likelihood of family breakdown and emotional damage. Incest is not necessarily harmful to the child, as evidenced in the case of two adolescents who had prolonged sexual contact with their parents without manifesting severe emotional disturbances. Incest generally occurs in highly disturbed families where the father feels rejected by an unloving or hostile wife and turns to his daughter. The wife may sanction the incest, and the daughter may encourage it because of a frustrating relationship with the mother. As divorces and remarriages increase, more incest problems involving stepparents can be anticipated. Preventive measures include legal adoption, and open displays of affection between remarried couples. Treatment of the sexually abused child must be individualized and depend on psychological development prior to the incident, as well as the family situation. In cases of incest where the child needs protection and the entire family needs treatment, the services of the child protection division of welfare departments are valuable. Children and parents should not be subjected to court appearances unless their evidence is necessary to prosecute a case. A bibliography of 16 references is appended.