A partial-equilibrium, two-country model is developed to analyze implications from the introduction of genetically modified (GM) products. In the model, innovators hold proprietary rights, farmers are (competitive) adopters, some consumers deem GM food to be inferior in quality to traditional food, and the mere introduction of GM crops affects the costs of non-GM food (because of costly identity preservation). Among the results derived, it is shown that, although GM innovations have the potential to improve efficiency, some groups can be made worse off. Indeed, it is even possible that the costs induced by GM innovations outweigh the efficiency gains.