"The reason we studied redheads in the beginning, it was essentially an urban legend in the anesthesia community saying redheads were difficult to anesthetize," anesthesiologist Dr. Daniel I. Sessler told the New York Times. "Redheads really do require more anesthesia, and by a clinically important amount," he added.
On top of that, the ginger-haired also need a heftier dose of local anesthetics, like Novocaine. As a result, they're two times less likely to visit the the dentist than their blond-, brunette-, and black-haired counterparts. It's all due to a mutation of the MC1R gene, which influences the redness of hair and lightness of skin. I wonder if any of these famous redheads experience dental anxiety? From the looks of their brilliant chompers, they don't.