Smarter men are delaying having children until later in life, study finds
[June 3, 2023: Staff Writer, The Brighter Side of News]
Researchers propose that men who score higher on intelligence tests tend to become fathers later in life compared to men with lower IQs. (CREDIT: Creative Commons)
Are men who become fathers after their 30th birthdays more intelligent? A new study seems to think so. With an extensive analysis of data, researchers propose that men who score higher on intelligence tests tend to become fathers later in life compared to their counterparts with lower IQ scores. Intriguingly, these same men are also more likely to have a larger number of children.
A vast dataset involving more than 900,000 Norwegian-born males born between 1950 and 1981 was used for this study.
These men had undergone an army conscription test in their teenage years, a process that entailed an evaluation of vocabulary, arithmetic, and figure-related questions.
Each participant was assigned a score representative of their IQ - a score of one corresponded to an IQ below 74, while the most intelligent individuals, with IQs above 119, received a score of eight. Alongside this, data concerning the age at which these men first became fathers, as well as the number of children they had, was gathered.
When researchers scrutinized the data, a distinct pattern emerged: those men who had higher IQs were older when they first became fathers, but also had more offspring. Interestingly, the study found high rates of childlessness amongst the lowest scoring group.
In discussing the findings, Dr Ole Rogeberg, one of the study's authors, stated: "Men who scored in the top 20 percent of cognitive ability had their first child at the average age of 30 and went on to have a total of two children. Meanwhile, men who scored in the bottom 20 percent had their first child at the average age of 27 and went on to have a total of 1.8 children."
The research, detailed in the journal Biology Letters by the team from the Ragnar Frisch Center for Economic Research, indicated that this pattern remained steady over time. Despite this, the researchers noted a decline in the rates of fatherhood both below the age of 30 and above the age of 35 in recent times.
Elon Musk with X AE A-XII Musk. Right: Elon Musk with Kai, Griffin, Saxon and Damian Musk. (CREDIT: elonmusk | Twitter)
Elon Musk, a father of 10 and with an alleged IQ score of 155, exemplifies this trend. Musk's first child was born in 2002, shortly before he turned 31. Tragically, the child passed away from sudden infant death syndrome at just 10 weeks old. In 2021, Musk welcomed his tenth child, Exa Dark Sideræl, with Canadian singer Grimes, via surrogate.
Other tech moguls reflect this pattern as well. Mark Zuckerberg, with an estimated IQ of 152, was 31 years old when his first child, Maxima, was born. There is no record of Bill Gates taking an IQ test, but it's no secret he co-founded Microsoft and was once the world's richest man. Gates was 40 years old when he had his first child, Jennifer, in 1996.
Change in fertility by age for three cognitive ability (CA) stanines and unscored men, 1950–1980. Imputed values for yet unobserved fertility marked in blue. (CREDIT: Biology Letters)
In a wider scope, over the last 250,000 years, 27 has been found to be the most common age for becoming parents. Additionally, fathers were consistently older than mothers, with an average age gap of 7.5 years, according to another study conducted by Indiana University.
However, age isn't merely a number when it comes to genetics. A child's DNA possesses between 25 and 75 genetic mutations differentiating it from its parents', and the types of these mutations depend significantly on the parents' ages at conception.
Mark Zuckerberg and his pediatrician wife Priscilla Chan with their first daughter Max. (CREDIT: AFP/Getty Images)
The researchers further enhanced their study by training a model to predict parental age using 25 million genetic variants in children with known parental ages at conception.
The correlation between intelligence, age at first-time fatherhood, and the number of children is a complex issue that provides us with fascinating insights into human evolution, reproduction, and societal norms.
The story it tells offers a compelling view of the role IQ may play in reproductive strategy, even if the causation behind the correlation remains up for debate.
For more science news stories check out our New Discoveries section at The Brighter Side of News.
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