The debate over labeling of genetically modified foods continues to simmer in the United States. Last week, the Center for Food Safety filed a legal petition with the U.S. Food and Drug Administration seeking mandatory labeling for foods made from crops that are genetically modified organisms. Activists are considering a California ballot initiative that would require the labeling of GMO-based ingredients in food.

American grocery stores began selling GMO foods in the 1990s and today stock thousands of items that contain genetically modified corn, soybeans and other crops. To date, no evidence has come to light indicating that foods developed using genetic engineering techniques pose risks greater than food produced using...