I have noticed that some human biodiversity or whatever people are so worried that intelligent people, especially women, make fewer children than some more average ones. But this is exactly as it should be. It is necessary that the birth rate in both ends of the distribution must be smaller than in the center level if the distribution is to be stable. It is also necessary that there is regression to the mean, which means that very clever parents do not often get as clever children as they are. It is mandatory that the IQ distribution stabilizes so that the variance does not constantly increase, everything must finally stabilize when the borders have been reached. Here is this situation: if clever people had as many children as average people, the variance would double in each generation. So, if you are very smart and have no children, you are doing fine. It will not make the world less intelligent. I wrote a short PDF of this problem, only a few very simple formulas in the following a link.