Sons of older dads are more intelligent, less concerned about fitting in with their peers and more focused on their interests, traits typically associated with being "geeky", finds a new study.
As part of the research, published in the journal Translational Psychiatry, researchers from King's College London and The Seaver Autism Centre for Research and Treatment in the US examined data from almost 8,000 UK-based twin pairs, who took part in the Twins Early Development Study (TEDS).
At the age of 12, twins completed a number of online tests designed to measure "geek-like" traits. Along with an IQ test, this also included questions around a child's level of "social aloofness."
Parents participated too, responding to questions about how concerned their kids were about fitting in with their peers and whether their kids had interests that took up a substantial amount of their time.
From there, the researchers computed what they called a "geek index" for each child.
The team found that overall, sons of older dads had higher geek index scores.
Kids with dads younger than 25 years old had an average geek score of 39.6. Those with dads aged 35 - 44 had a geekiness level of 41, while offspring with dads over 50 (hello George Clooney) averaged geek scores of 47.
The effect remained even when a parents' socioeconomic status, qualifications and employment were all taken into account. Maternal age, on the other hand, had almost no impact at all on geek index scores.
The researchers also found that several years after completing the study, those high on the geek scale did better in school exams, particularly in science, technology, engineering and mathematics (STEM) subjects.
"Our study suggests that there may be some benefits associated with having an older father," said lead author Magdalena Janecka in a statement. "We have known for a while about the negative consequences of advanced paternal age, now we have shown that these children may also go on to have better educational and career prospects.'
What the study didn't explore was exactly why older dads might have geekier sons. According to the authors, it may be due to older fathers having more established careers and a higher socio-economic status, meaning children have access to better education and more "enriched environments".
But what about girls? Why don't older dads have geekier daughters, too?
Speaking to The Guardian, Ms Janecka suggested that her team may not have adequately captured the geekiness of girls.
"Maybe we aren't measuring geekiness properly," she said. "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."