Grisha Perelman is one of the winners of the 2006 Fields Medal, though he has declined to accept it. The other three winners are Andrei Okounkov, Terence Tao and Wendelin Werner.
I am glad that I happened to sit for Okounkov's course on Representation Theory while I was in Princeton. He was a very lucid and friendly teacher.
Terence Tao is only 31. Swap the digits in 31, you get 13. The age at which he won a gold medal at the Internation Mathematics Olympiad, a feat which hasent been achieved again yet.
Some kids start thinking about primes while others of their age are still learning to use the potty. What else can you say ?