In a now-famous segment of his talk show, Jimmy Kimmel sent a reporter out to a West Coast farmers market in 2014 to ask food-conscious shoppers what they thought of GMOs. All the interviewees declared their horrified avoidance of GMOs—and then, predictably, failed to come up with an explanation for what the letters “G.M.O.” stand for.

The answer, of course, is “genetically modified organism.” First launched commercially on a wide scale in U.S. agriculture in 1996, GMOs are typically plants or animals whose genomes have been...