Several nation states have reasons to halt the import of genetically modified organisms. The current international trend towards a regime of free trade makes such bans problematic. Whether a nation state is deemed justified in banning a certain product is strongly connected to discussions about what are acceptable criteria for proof of risk. The determination of these criteria hinges upon considerations of individual and national autonomy. This paper compares two different points of view in the debate: the WTO opposed to the UN. A distinction between internal and external autonomy explains the differences in approach between the UN and the WTO. The conclusion is reached that adequate respect for autonomy requires a certain amount of flexibility in the criteria for proof of risk.