Modern psychology draws attention to the determinants of incest and the mechanisms leading to incestuous psychological and biological contacts. It addresses the issue of the negative consequences of incest in the form of distorted sexual behavior and the disrupted individual and social functioning of the victim.
The paper presents a case study of a thirteen-year-old girl abused sexually by her two biological brothers. The sexual contacts with both brothers took place within the same period, and both brothers knew about it. The case study covers not only the relationships between the perpetrators and their underage sister but also the family situation and the developmental problems of the girl. The case study describes the developmental, social, and physical context of the sexual abuse. It also includes the results of psychological examinations of the victim and analyses the psychological assessment criteria for the credibility of her testimony. The situation is addressed from two perspectives: life-centered, focused on the relationship aspect and the dynamics of the crime; and legal, involving the exposure of the crime and the resulting individual and system (familial) changes.