[g00dn3ss]

Here is a pop-sci version of some recent research:

http://www.sciam.com/article.cfm?id=the-secret-to-raising-sm...

However, this isn't particularly surprising. Research on "grandmasters" in many activities, like chess or pilots, usually shows they've put in 25K hours of practice in their field.

I'm certainly not in favor of saying anyone can do anything. Especially in physical activity. There are definitely physiological advantages.

The same is also true in mental activities to some extent. A kid with down syndrome probably isn't going to become a math professor. However, I think the point is that most normally developed folks probably haven't hit a ceiling in their math aptitude. They just stopped caring or putting in the effort.