“So how do I make my little boy as clever as you are?” The question came out of nowhere. We were teenage waitresses in a Wimpy hamburger joint in a working-class town in England, taking our break squeezed together in a little red naugahyde booth, chowing down on the greasy burgers the management allowed as afternoon snacks. I paused, mid-bite, and turned to look at my co-worker. She wasn’t mocking me, as some of the girls might have. After all, I was a Scot, the only kid who worked in the café who didn’t come from a Cockney home, and, even more awkward, the only one who had any hope at all of...