Older men tend to have “geekier” sons who are more aloof, have higher IQs and a more intense focus on their interests than those born to younger fathers, researchers claim.
The finding, which emerged from a study of nearly 8,000 British twins, suggests that having an older father may benefit children and boost their performance in technical subjects at secondary school.
Researchers in the UK and the US analysed questionnaires from 7,781 British twins and scored them according to their non-verbal IQ at 12 years old, as well as parental reports on how focused and socially aloof they were. The scientists then combined these scores into an overall “geek index”.
Magdalena Janecka at King’s College London said the project came about after she and her colleagues had brainstormed what traits and skills helped people to succeed in the modern age. “If you look at who does well in life right now, it’s geeks,” she said.
Drawing on the twins’ records, the scientists found that children born to older fathers tended to score slightly higher on the geek index. For a father aged 25 or younger, the average score of the children was 39.6. That figure rose to 41 in children with fathers aged 35 to 44, and to 47 for those with fathers aged over 50.
The effect was strongest in boys, where the geek index rose by about 1.5 points for every extra five years of paternal age. The age of the children’s mothers seemed to have almost no effect on the geek index.
When the scientists looked at the children’s achievements at school they found that having a high IQ, a tendency to focus intensely and social aloofness were all linked to children taking more technical GCSEs. When children displayed all three traits, the effect was even more pronounced, the researchers write in the journal Translational Psychiatry. Overall, children who were born when their fathers were 50 or older were 32% more likely to achieve two A or A* grades at GCSE than children born to men aged under 25.
Janecka said the study is one of the first to suggest that having an older father can have benefits for a child. Previous work by Janecka and others has found that children born to older men are more at risk of medical conditions including autism and schizophrenia.
The scientists calculate that 57% of the geek index score is inherited, but that figure is likely to vary with age. If right, it suggests that DNA and the environment have roughly an equal share in how geeky someone turns out. Writing in the journal, the researchers speculate that there may be some overlap with genes that contribute to autism and a high score on their index.
If the findings are right, it is unclear why the effect is different in boys and girls. Janecka said that the study may simply have failed to capture how girls display geekiness. “Maybe we aren’t measuring geekiness properly. They may be geeky in a different way to boys,” she said. But it is also possible that whatever averts autism in girls – five times as many males are diagnosed than females – also shields them from the most geeky traits.
Research is under way to recognise why older parents are more likely to have children with particular mental disorders. One theory pinpoints mutations that build up in parents’ sperm and eggs. But with geekiness, the answer could lie in geekier men simply being more likely to delay fatherhood.
“Certain men who delay fatherhood tend to be better educated and have better jobs and a higher geek index and they pass those genetics nto their offspring,” said Janecka. “It causes them to delay fatherhood, but other factors might contribute too.”