This has been know for some time, but in vitro kids have an higher IQ than the average (whether IQ is an accurate measure of intelligence is a debate better left for another day). Even advanced in vitro techniques lead to smarter kids.
So, people, if you want to have smart kids, in vitro is the way to go!
Consider, also, as a factor, that in vitro mothers are more likely to keep their kids at home with them. Some have argued that in vitro kids suffer from delayed social development. Yet, interestingly, they don’t suffer for delayed intellectual development, quite the opposite apparently.
I think we still need to learn a lot about what makes a smart kid.