Genetic modification in the United States and Canada has not accelerated increases in crop yields or led to an overall reduction in the use of chemical pesticides. The promise of genetic modification was twofold: By making crops immune to the effects of weedkillers and inherently resistant to many pests, they would grow so robustly that they would become indispensable to feeding the worlds growing population, while also requiring fewer applications of sprayed pesticides. Twenty years ago, Europe largely rejected genetic modification at the same time the United States and Canada were embracing it. Comparing results on the two continents ... shows how the technology has fallen short of the promise. The United States and Canada have gained no discernible advantage in yields - food per acre - when measured against Western Europe. Also, a recent National Academy of Sciences report found that there was little evidence that the introduction of genetically modified crops in the United States had led to yield gains beyond those seen in conventional crops. At the same time, herbicide use has increased in the United States. And the United States has fallen behind Europes biggest producer, France, in reducing the overall use of pesticides, which includes both herbicides and insecticides. Pesticides are toxic by design ... and have been linked to developmental delays and cancer. The same companies make and sell both the genetically modified plants and the poisons.