In 2000, a landmark study claimed to set the record straight on glyphosate, a contentious weedkiller used on hundreds of millions of acres of farmland. The paper found that the chemical, the active ingredient in Roundup, wasn’t a human health risk despite evidence of a cancer link. Last month, the study was retracted by the scientific journal that published it a quarter century ago, setting off a crisis of confidence in the science behind a weedkiller that has become the backbone of American food production. - snip - The 2000 paper, a scientific review conducted by three independent scientists, was...