Embryo Selection for Intelligence

While this is a very exhaustive and eloquent argument in favor of embryo selection, it seems that (at first glance) some important risks are not really addressed.

For example, what if social dysfunctionality is a function not only of individual intelligence but also of the distribution of intelligence across the population? There may be negative consequences from an overall upwards shift. (Crude analogy: Compare the discussion on the threat of a surplus of young males in societies).

What if the reported effects are non-linear, i.e. distinct between sub-mean and above-mean intelligence?

Given our extremely lacking understanding of how societies work in general (i.e.: financial markets, social unrest, individual happiness etc.), I am really hesitant to believe that we are able to anticipate even a tiny amount of such an approach's implications.

And, of course, embryo selection would violate several fundamental humanist values - would society need to penalize people for opting out? Are we confident enough in society's self-regulating mechanisms to trust that such an instrument would be always used ethically?

Interfering with children is so terrifying because the fallout lasts a hundred years. That calls for some more humility, I think.