Fears about the harmful effects of eating G.M. foods have proved to be largely without scientific basis. The potential harm from pesticides, however, has drawn researchers’ attention. Pesticides are toxic by design — weaponized versions, like sarin, were developed in Nazi Germany — and have been linked to developmental delays and cancer.
“These chemicals are largely unknown,” said David Bellinger, a professor at the Harvard University School of Public Health, whose research has attributed the loss of nearly 17 million I.Q. points among American children 5 years old and under to one class o