In this article we address the construction of an etiology of rape, from the field of Legal Medicine and Criminology, during the first half of the 20th century in Chile. We hypothesize that in the aforementioned process a biological and social determinism was reinforced, articulated, in part, through the naturalization of male sexual violence perpetrated against women, as well as its association with certain social groups. Through the discursive analysis of monographs, didactic works and articles, we verify how, depending on the circumstances, the commission of this criminal typology was assimilated within the confluence of two interpretative tendencies, compatible and, at the same time, not exempt from contradictions. In this sense, rape was interpreted as the materialization of a psychopathology associated with the categories of perversion and dementia, while conceived as an expression of a transversal, natural and instinctive male inclination towards the exercise of violent sexuality. We consider that it was the result of the interaction between socio-ethnic and gender ideological conceptualiza- tions with a particular reformulation of certain theoretical references, based on the European fin-century positivist criminology.