Smart people have less children
This is not dysgenic. Low IQ population have r reproductive strategy. High IQ people have K reproductive strategy. Rushton has made it clear. High IQ people are forever minority.
r strategy people do have more kids. But r people survival rate is also low. They are the first victims of famine. They are usually cannon-fodder. They live shorter life. They need to sexually mature fast and be sexually attractive at younger age to reproduce as early as possible. Their population expand fast at good time and shrunk fast at bad time. K strategy population however is relative stable in both good and bad time. Believe or not, Carl Max has studied proletarian population (r strategy population) behaving such way.