Clever men are more fertile and have more children, according to science.
What does a person’s IQ have to do with how many children they’re likely to have? According to a newly published study, clever men with higher IQs are more fertile, and tend to have more children than men with lower IQs.
In this study, scientists from University of Stockholm looked at a database of IQ scores of Swedish men born between 1951 and 1967. There were 779,000+ records in the database, and scientists pitted this data against information showing how many children each man went on to have, before drawing their conclusions.
According to scientists, there was a “positive relationship between intelligence scores and fertility”, with the pattern being consistent across all cohorts studied. All in all, men with the lowest categories of IQ scores had the fewest children. On the flip side, clever men – or men with the highest IQs – had the most children.
Higher IQ = increased fertility
Now, you might be wondering: is it possible that a third factor (such as background, socio-economic status, etc) could have influenced both these men’s IQ scores and fertility?
Well, in trying to account for other possible causes, researchers controlled for additional factors such as levels of education and parental background in the study. After making these adjustments, they found an even stronger positive relationship between IQ and fertility.
For instance, to assess the impact of family background, the scientists looked at how many children brothers in the same family had. Here’s what they found: a brother with the lowest category of cognitive ability was likely to have 0.58 fewer children compared to a brother with an IQ of 100. A brother whose IQ was in the highest category, on the other hand, would have 0.14 more children than someone of average IQ.
Why does lower IQ lead to lower fertility?
Why do clever men tend to be more fertile than men with lower IQ? While scientists aren’t 100% sure as of now, one possible reason is that having a low IQ score is “closely linked” to poor health in childhood. Again, we don’t have conclusive evidence showing why this is the case, but it seems as though this factor (poor health in childhood) may influence the number of children one goes on to have.
While similar studies haven’t been done in other regions, the authors say that this trend in Sweden is likely to play out in other countries as well. So look around at your friends and acquaintances, and see which of your friends have the large families… these might very well be the folks who have higher than average IQs!