This thesis examines medical approaches to sexual offences in England between 1850 and 1914, with particular attention to law-making and judicial processes. It addresses two key research questions. Firstly, what was the place of medicine in shaping the law on sexual consent and in the implementation of laws on sexual crime? Secondly, can the analytical category of age be used to understand such medical roles? In addressing the first research question, the thesis shows that relationships between medicine, the law and wider society can be understood in terms of negotiation and shared pools of knowledge rather than impact. It demonstrates that medical ideas on sexual crime and sexual consent were deemed sufficiently valuable to be drawn upon widely by different groups, but they were not imposed ‘from above’ by a coherent medical profession. Medical roles thus need to be studied and understood rather than either oversimplified as ‘dominant’ or dismissed as non-existent. In addressing the second research question, the thesis argues that age has been unduly overlooked as a category of analysis in historiography. It shows that ideas about sexual crime shifted in relation to victims of different ages and that age can productively be situated in relation to other analytical categories, particularly class and gender. By moving beyond treating ‘children’ and ‘adults’ as homogeneous categories, this study opens up new ways of understanding histories of medico-legal relations and sexual crime.AHR