Is normality - or conformity to certain parameters of behaviour and appearance - a necessary condition of all advanced societies or a tyranny which constrains individual aspiration and social evolution? Do conceptions of normality have any objective basis or are they merely social constructions, inexorably tied to the exercise of political and economic power? These questions have troubled some of the influential minds of the last two centuries but are they still relevant today, as conceptions of normality are challenged by advances in genomics and new technologies of human enhancement?