Children with Severe Hyperactive Syndrome had elevated lefthandedness, were largely blond and blue eyed, with cases of autism and dyslexia. (Behan, P. & Geschwind, N. (1985). Dyslexia, congenital anomalies, and immune disorders: The role of the fetal environment. Annals of the New York Academy of Sciences, 457, 13-18.)
Anthropologist Marvin Harris hypothesized that Scandinavian need for Vitamin A and D propelled lighter skins to absorb light and an ability to process dairy. By acquiring the lighter skin, blue eyes and lactate processing abilities of infants, humans living in far Northern climes could more easily survive.
One could also estimate that there would be a larger percentage of left handers (infants are random handed) among these people. If the autistic are blond haired and blue eyed a higher percentage of the time, exhibiting maturational delay with these infant features, does this suggest that Scandinavian populutions should have higher percentages of autism?