In contemporary debates about the nature of bioethics there is a widespread view that bioethical decision making should involve certain knowledge of and respect for cultural diversity of persons to be affected. The aim of this article is to show that this view is untenable and misleading. It is argued that introducing the idea of respect for cultural diversity into bioethics encounters a series of conceptual and empirical constraints. While acknowledging that cultural diversity is something that decision makers in bioethical (...) contexts should try to understand and, when possible, respect, it is argued that this cultural turn ignores the typically normative role of bioethics and thus threatens to undermine its very foundations. (shrink)