This article examines the doctrine of infanticide in relation to the norms and practices of criminal responsibility. It adopts an historicized approach to the law, which reveals that the legal proscription of child killing by mothers began as an instance of the principles of criminal liability that have been labelled ‘manifest criminality’. With changes in the social meanings accorded to women who kill their children in the 18th and 19th centuries, however, the law of infanticide developed into an instance of (...) what I call ‘manifest madness’, which is an analysis of the way that ‘madness’ is constructed in and through criminal law practices. According to this analysis, a particular social type, the infanticidal woman, has come to determine the legal issue of the defendant’s criminal responsibility, and the act of infanticide has become an instantiation of abnormality for criminal law purposes. In the absence of an expert medical consensus, the ‘strange’ doctrine of infanticide is sustained in the current era by a lay or non-expert knowledge about the interrelation of gender, childbirth and madness, which underpins legal evaluation of infanticidal women and their acts. (shrink)