Terman's studies were groundbreaking at the time, but they have lots and lots of holes.
The bigger problem is that we don't know if that's how it was back then, or if parenting/schooling accomdiations will have changed things.

Look for Dr. Tracy Cross http://www.bsu.edu/edpsych/profile/0,1396,3604-639-29214,00.html
for more up to date studies of gifted kids if you have any particular question you are curious about.

Smiles,
Grinity

Coaching available, at SchoolSuccessSolutions.com