Title is misleading (see conclusion below). It could also be interpreted that higher intelligence leads to delayed family formation (for a myriad of reasons),

Title is misleading (see conclusion below). It could also be interpreted that higher intelligence leads to delayed family formation (for a myriad of reasons), which necessarily involves less offspring. Conclusion: The present study revealed a complex association between intelligence and childlessness. The mediated association between the highest stanine intelligence score and childlessness was interpreted as an expression of delayed family formation. It is still unclear whether this delay in family formation will “catch up” if childlessness is measured at an older age, which raises the need for additional studies on the subject.