Ben Ofori-Okai learned the difference between an MD and a PhD at a younger age than most when someone introduced his father, a chemist, as “Dr. Ofori-Okai.” “I was only 4 years old, but I remember thinking, ‘My dad’s not a doctor. He doesn’t treat people,’” Ofori-Okai says. “That’s when I learned that there was a different kind of doctor: a scientist.”