What do Stephen Hawking and Albert Einstein have in common with a 4-year-old girl? In one specific case, their I.Q. score. Heidi Hankins—whose father just happens to specialize in measuring children’s intelligence—is one of few to boast a 159 I.Q.. The gifted Hankins, who taught herself to read at 18 months, is now a member of Mensa, an organization for those with an I.Q. in the top 2 percent …
