Controversy over the use of genetically engineered (GE) crops may have induced some farmers to disadopt these seeds, making a traditional diffusion model inappropriate. In this study, we develop and estimate a dynamic diffusion model, examine the diffusion paths of GE corn, soybeans, and cotton, predict the adoption of those crops over the next two years, and explore the main determinants of the diffusion rate. Our estimates indicate that future growth of Bt crops will be slower or negative, depending mainly on the infestation levels of the target pests. Adoption of herbicide-tolerant soybeans and cotton will continue to increase, unless consumer sentiment in the United States changes radically.