Among his findings was that something like 90% of autistics have an engineer, mathemetician, or musician, in their close family -- father, mother, grandfather, uncle, aunt. That one lept out at me and made me wonder why ALL of my grandchildren were not autistic, to say nothing of my own kids!
My brother was a musician, a brilliant musician and mathemaetician. My brother had full scholarship to MIT before he left for the New England Conservatory of Music. And my sister-in-law's Father was an engineer of the highest caliber. She herself a very talented musician.
Music and mathematical talent often go hand and hand. I think the scientists say they use the same part of the brain. Of course, engineering relys heavily on mathmatics.
But Sowell's findings could be subjective too. I suppose he could have made a case that the close relatives of his autistic study group all spoke English too!