In the 1930s there was a huge amount of study of skull shape as a delineator of natural intelligence and personal characteristics by a certain mid European country.
The entire science is now discredited.

I would expect fingerprint analysis as an indicator of intelligence, personal, and racial characteristics to end up in the same trash bin.

As for nature vs. nurture, I think it's pretty obvious poor nurturing can hurt natural intelligence, but you can't nurture a potato into an Einstein,
even if you cuddle it... a lot.

The American Education system is neck deep in this experiment and every one involved I know personally (teachers, special workers, psychologists) all say it's a fairly large belly flop so far.

Jammer