Judging by recent headlines, young men and women are more politically divided now than ever before. “A new global gender divide is emerging,” the Financial Times data journalist John Burn-Murdoch wrote in a widely cited January article. Burn-Murdoch’s analysis featured several eye-popping graphs that appeared to show a huge ideological rift opening up between young men and young women over the past decade. The implications—for politics, of course, but also for male-female relations and, by extension, the future of the species—were alarming. A New York Times opinion podcast convened to discuss, according to the episode title, “The Gender Split and the ‘Looming Apocalypse of the Developed World.’” The Washington Post editorial board warned, “If attitudes don’t shift, a political dating mismatch will threaten marriage.” But nearly as quickly as the theory gained attention, it has come under scrutiny. “For every survey question where you can find a unique gender gap among the youngest age cohort, you can find many other questions where you don’t find that gap,” John Sides, a political-science professor at Vanderbilt University, …