This paper discusses the potential harms involved in biobank research and how ethical review, informed consent, withdrawals, and anonymization of samples should be handled in the light of these harms. There is less risk involved in biobank research than in human subject research; it should therefore be treated differently. In our view, anonymization should not be an automatically permissible response to requests for withdrawal. Nor should a request for withdrawal necessarily stop research on identifiable samples. Apart from not being particularly appropriate for protecting the interests of individuals, anonymization of samples has a negative impact on research. We suggest that the current view on withdrawal from research, supported by the Declaration of Helsinki and subsequent ethical guidelines, be abandoned in the context of biobank research and be replaced by an approach inspired by the Nuremberg Code. This approach requires those wishing to withdraw their samples from research to present sufficient reason for doing so. Our interpretation of 'sufficient reason' includes all those involving genuine, deeply felt concerns that are not based on misconceptions. Still, this underlines the fact that we all share a responsibility for health research and that no one should take withdrawal from biobank research lightly.