Earlier quoted context omitted.
It depends. As we know intelligence is highly heritable and an extremely large component of one's productivity, it may make more sense, in terms of having an impact, for extremely high-IQ people to focus on have a large number of children, especially considering how rare having a large number of children is among those with high IQs.
I think the “intelligence” we are talking it is more a mix between nature and _nurture_. So it is not enough just for people with high IQ to have many children. The adult needs to follow their passion/dream/work to develop the intelligence and contribute back to the society.
Smart people having more kids is not the full solution, but it is a part of the solution, and a neglected one. People already talk about improving education a lot. But it seems that education can only go so far -- some children get better results unschooled than other children get in schools.