Read 'Unlocking the Clubhouse' (in regard to women.) It's dated but more recent research has similar conclusions.

I can't speak personally about race issues in tech. What I do know is that the industry thrives on ideas, and as people themselves have diverse ideas, missing an entire group's is missing a lot. Why isn't the field more racially diverse? Are black people 'naturally not interested in tech'? Or do they face social barriers others don't? What I know leads me to believe the latter.