From U.S. presidents to elite athletes, lefties have turned what was once a stigma into a surprising advantage.

While the days of forcing left-handed children to use their right hands are mostly over, the bias against lefties continues in most languages around the world.

We’ve all heard the whispers. Those southpaws among us supposedly have some kind of secret intellectual edge. From Leonardo da Vinci sketching with his left hand to Einstein supposedly jotting down ...