This is a qualitative study with a perspective of social-construction. By using a discourse- analytic method the purpose of the study has been to examine witch prevailing discourses concerning sex and sexuality that marks the social work praxis of the definition ”boundless sexual behavior”: a conception witch in some context is used within the social work concerning young girls and their problems. The investigated material is based on two “open” (unstructured) interviews with social practitioners who works at an institution were young girls and women are taken care of by law. This has further been connected to relevant literature concerning sex, gender and sexuality. The study reveals that the prevailing discourses is marked by a sex/gendered conception of the world containing generalisations, myths, stereotypes and objectifications. The girls are constructed and reduced as traumatized victims and manipulative seducing sex-objects. Whose sexuality isn’t expressed as their own but as tied to the man. The men on the other hand are reduced as infantilized and dehumanized victims of socio-cultured and biological inheritance. Despite that the definition ”boundless sexual behavior” can’t be defined according to any theories, directions ore ”officially” settled instructions, the term is applied as a “common sense” concept within the social work praxis. For us, a remarkable phenomenon is that this label almost exclusively is applied on to girls’ sexuality. However the divergence between the sexes has serious consequences fore those included in the category. The girls are constructed as sexual “problem holders” and are stuck with this label in their social journals.