This paper discusses entanglements of science and ethics in the regulation of genetically modified crops. Using the 2009 German ban of genetically modified maize MON810 and debates concerning the quality of science cited to support it, the paper highlights how values are tacitly embedded in science for policy and how ethical questions permeate the way this science is developed, quality-controlled, and given authority in the European regulation of biotechnology. We argue that a lack of recognition and inadequate treatment of such value-commitments influencing science, and through this policy, impinges upon and weakens the ethical standards involved. This has particular significance as Europe debates genetically modified crop legislative reform.