I have actually come across one or two studies in this general direction. There is some good information there. Unfortunately, I find it troubling that their definition of mathematically talented is 95th percentile (or even 99th percentile). Dr. Stanley's work focused on children who were really at the extreme tail (even well beyond the 99.9 subtest standard used by Davidson). At the nationally competitive level, that's who we are dealing with.

Even my DD, who is not mathematically talented, is consistently at above 99th percentile. She is just not at the extreme like her brother or even her mother.