This to me is one of the most apparent failures of modern taboo infecting people's ability to communicate, or even reason.

Eugenics is not ethical, for a variety of very good reasons; that does not mean that it's unscientific.

We know that intelligence is heritable; we have observed epigenetic group trends like the Flynn effect to the point where they plateau...

The biggest unknown in my opinion is how stable the gains we have made are. If we have our education systems disrupted, or some nutrition crunch, does the population average drop to the point where the complex systems we depend on are not maintained?