In this article we examine ethical aspects of the involvement of children in clinical research, specifically those who are incapable of giving informed consent to participate. The topic is, of course, not a new one in medical ethics but there are some tensions in current guidelines that, in our view, need to be made explicit and which need to be responded to by the relevant official bodies. In particular, we focus on tensions between the World Medical Association Declaration of Helsinki, and the guidance offered by the British Medical Association, the Royal College of Paediatrics and Child Health (formerly the British Paediatric Association), and the Council for International Organizations of Medical Sciences. We conclude with a call for these organisations to make their guidance explicit in relation to the World Medical Association Declaration.