So is nurture, people go to school in different years from their siblings (and parents) etc. and so on.
So it would be a lot stronger case for genetics (assuming it's supposed to be one, and not just a tangential anecdote) if they'd said "No one ever spoke to us but all 7 of my brothers and sisters became top engineers, just like our parents, uncles and cousins (that we'd never met)".
As it stands it seems to recommending having some kind of fortitude (which isn't taught via nurture, or inherited via genetics) as the key element.
So it would be a lot stronger case for genetics (assuming it's supposed to be one, and not just a tangential anecdote) if they'd said "No one ever spoke to us but all 7 of my brothers and sisters became top engineers, just like our parents, uncles and cousins (that we'd never met)".
As it stands it seems to recommending having some kind of fortitude (which isn't taught via nurture, or inherited via genetics) as the key element.