Genetically Engineered Crops: Experiences and Prospects

Since their introduction in the mid-1990s, genetically engineered (GE) crops have been the topic of much debate. This report reviews evidence accumulated from experiences on the most widely grown GE crops to date: herbicide-resistant and insect-resistant varieties of maize, soybean, and cotton. While recognizing the inherent difficulty of detecting subtle or long-term effects on health or the environment, the study committee found no substantiated evidence of a difference in risks to human health between current commercially available genetically engineered (GE) crops and conventionally bred crops, nor did it find conclusive cause-and-effect evidence of environmental problems from the GE crops. There are areas where some weeds and insect pests have become resistant to Bt toxins in insect-resistant crops and to glyphosate used with herbicide-resistant crops. GE crops have generally had favorable economic outcomes for producers in early years of adoption, but enduring and widespread gains will depend on institutional support and access to profitable local and global markets, especially for resource-poor farmers. Recent advances in molecular biology, such as the development of the CRISPR/Cas9 genome-editing tools, have the potential to increase the diversity of genetically engineered traits and the kinds of crops that are engineered. All technologies for improving plant genetics--whether GE or conventional--can change foods in ways that could raise safety issues. Therefore, to keep pace with new developments, regulatory systems will need to focus on the risks that may be posed by new crop varieties rather than on the processes and technologies used to make them. The report recommends the development of a tiered approach to safety testing using as criteria novelty (intended and unintended), potential hazard, and exposure