Smarter women have fewer children, researcher discovers

Former Prime Minister Helen Clark has no children. Photo / Janna Dixon

Women lose a quarter of their maternal urges for every 15 extra IQ points they have, according to international research.

And this may contribute to a dumbing down of society over time.

Research by London School of Economics psychologist Satoshi Kanazawa also found more intelligent people were more likely to drink, smoke and take drugs because "they are evolutionarily novel".

Using data from Britain's National Child Development Study, Mr Kanazawa studied the links between intelligence and maternal urges in women. He found more of the former meant less of the latter.

Even after adding controls for economics and education, the results remained the same - the more intelligent the woman, the less likely she was to have children.

Mr Kanazawa published his findings in his book, The Intelligence Paradox, and the research into the number of children compared with IQ was in the chapter titled "Why intelligent people are the ultimate losers in life".

He found that the more intelligent both men and women were in their childhood, the fewer children they wanted when they were older. Those who wanted no offspring when they were young had a mean IQ of 105.5, almost 7 points higher than those who did want children.

But while the level of intelligence affected whether women reproduced later in life, it did not affect men.

Mr Kanazawa, who lived in Christchurch for a year, said: "More intelligent women have fewer children in their lifetimes than less intelligent women. In contrast, more intelligent men, despite having wanted to have fewer children at age 23, do not actually have fewer children by age 47."

And he did not believe that smart women choosing to not have children had anything to do with their desire to pursue academics or a career. The psychologist believed that only childhood intelligence, not educational achievement or earnings, decreased the number of children women had.

This could have a negative impact on how smart society was.

"If more intelligent women have fewer children, and are more likely to have fewer children, and are more likely to remain childless, then one potential consequence is that the average level of general intelligence in society may decline over time."

Mensa New Zealand member and clinical psychologist Dr Aloma Parker said the lowering of society's general intelligence was a possibility, but unlikely because research showed traits tended to drift back to the norm.

Dr Parker has an IQ of above 133 and is in the top 2 percentile. She also has two children.

But she agrees that smarter women do have a tendency to have fewer children, especially since the advancement of birth control.

Successful Kiwis

• Helen Clark: Former Prime Minister - no children

"Having children has never been something I've wanted to do because I value my personal space and privacy too highly. I cannot think of the sort of life I would want to have where I would want to give up those things for children.

"I've observed many friends and relatives with children over many years, and nothing that I've seen has led me to change my mind. I don't think it's just this job.

"The other thing is, I spend my whole life working with and on behalf of people. I take my hat off to people who can add families and family concerns on top of that, but I just don't think I could happily do it."

- Making Policy Not Tea, a 1993 book about women MPs

• Theresa Gattung: Former chief executive of Telecom - no children

• Annette Presley: Co-founder of ISP Slingshot - two children

Intelligent people according to Satoshi Kanazawa

• Liberals
• Atheists
• Night owls
• Homosexuals
• Childless
• Classical music lovers
• Binge drinkers, smokers