>Consider this: height is a pretty straightforward characteristic, and it's known to be highly heritable (tall parents = tall children). In fact, 80% of the v

>Consider this: height is a pretty straightforward characteristic, and it's known to be highly heritable (tall parents = tall children). In fact, 80% of the variance in height is known to be genetic The genetics of human height is much more complicated than he summarises here. In short, environment has a lot to do with height, and there's regression towards the mean too, which leads to children of tall parents being smaller (but still relatively tall). Wikipedia has a good article on it (citing 60-80% heritability): https://en.wikipedia.org/wiki/Human_height https://en.wikipedia.org/wiki/Human_height