The article reveals how the construction of genders and of warfare's contribution to the creation of society are intrinsically related. Following the alternative question of “how one learns not to aggress?”, the author suggests that warfare is not a continuation of our animal violence and points out to the prohibition of violence that lies at its origin. Tracing back this prohibition to the “sibling trauma” of the toddler enables us to gain an understanding of the horizontal “Law of the Mother” . The mother's law prohibits sibling or sibling-substitute murder and sibling incest. In the article, Mitchell discusses the outcomes of this first absolute law of infancy and suggests that warfare is gendered not just incidentally but in its very construction.