Male child sexual abuse is hereby studied under the gender and transgenerational perspective. We present a case study of a boy who started to suffer sexual violence when he was ten years old. The context: Multifamiliar Group (MG). The instruments: observation of the interactions, dialogues and semi-structured interviews. Informations: organized as from the violence and transgenerational history, construction of the Genogram and of the Family Life Cycle, of the data of the attendances and of the present situation of the family. The results indicate a context of multiple needs; a familiar organization with conflicts regarding the protection duties as well as alcoholism and sexual rap seen as elements of a privileged malehood.