A player looks on from the dugout during a baseball game at Kentlake High School in Kent, Wash., on May 4, 2025. According to a survey by the Aspen Institute, 11.4% of parents believe their children can play professionally. (Grant Hindsley/The New York Times) By Ken Belson Like many mothers in Southern California, Paula Gartin put her twin son and daughter, Mikey and Maddy, into youth sports leagues as soon as they were old enough. For years, they loved playing soccer, baseball and other...