...Wanna know how to ruin a boys life? Compliment his intellect. Tell him he can do anything. This works especially well if elementary school teachers, family friends, church friends, sunday school teachers, librarians, and the random coworker of a parent all say the same thing. Saying "I'm thinking you're going to do something great, like cure cancer. You never give up on anything" also does the trick.
I learned to read before I was old enough to go to preschool, due to both my parents being teachers. Up until 9th grade, every year my principal or teacher would ask me to move up a grade. But here's the kicker, just because you start off light years ahead of the other kids...doesn't mean you're going to stay that way. "I'm smart, I don't need to study" becomes a common thought process. Soon you're like "meh, low A on this test...but I didn't study and these kids wasted their lives to get two more points than me." Soon, the acceptance of a low A became a high B, accepting a high B became a middle B. Just an average student then. And through it all, you're still being told that you'll cure cancer or do something miraculous.
Moral of the story, frequently telling someone that you have high expectations of them and that they are meant to do something awesome in this world, even if its just a compliment or a morale booster, will lead to some intense problems later in life when you're just one of thousands of students at your school doing your premed major.