IQ and genetics

One of the more common questions of smart people: how do I make my kids inherit my intelligence? While there is no definite answer, we have some good ideas of what should or should not be done. Read more here,  here, here, here, and here.

Beware of what you wish for

Before we continue, a small warning. The genes that are responsible for high IQ may also cause autism.  As we climb up the IQ ladder, there are more kids on the spectrum or with social difficulties. For example, Albert Einstein’s son had a mental disease.

It is also not very clear if extremely high intelligence contributes to extremely high achievements. The correlation goes up until we reach the IQ of 125. Then there is a plateau, and above 160, the achievements start to go down due to antisocial behavior and boredom.

What is the effect of genetics on intelligence?

In one study, a person taking the same test twice without additional preparation has a 90% correlation between the results. Identical twins raised together have an 80% correlation. When they are raised apart the correlation is 70%. Adopted children raised together have a 40% correlation.

This means that genetics is much more correlated is IQ than upbringing. However, if there is no genetic correlation, upbringing also has a strong effect. We can say that the genetic element is around 60% of the IQ score, the upbringing around 30%, and pure luck 10%.

The IQ itself is not 100% correlated with achievements. Emotional intelligence is often better correlated with what we consider to be a success. And in emotional intelligence, upbringing is significantly more important than genetics.

Mother or father?

Almost all of the genetic markers responsible for intelligence are located on chromosome X. This means that boys inherit intelligence from their mothers, and girls equally from mother and father.

However, the Y chromosome is often responsible for epigenetics. What does that mean? A mother can be not very smart herself, but pass “smart” genes to the children. Moreover, boys are much more likely to suffer the autistic part of the intelligence genes.

Autism was found to occur more often in families of physicists, engineers, and scientists. 12.5% of the fathers and 21.2% of the grandfathers (both paternal and maternal) of children with autism were engineers, compared to 5% of the fathers and 2.5% of the grandfathers of children with other syndromes.

My grandfathers and father were engineers, so I was relieved to learn that Anna’s father was a medical doctor.

What can we do about it?

It is very little we can do about genetic factors. We (probably) do not live in countries with arranged marriages and finding a soulmate is already very difficult. I do not think anybody performs genetic tests before the actual pregnancy. From what I know, checking astrological synastry is more common than a genetic test.

Somehow we hope that the kids will inherit the brains of their fathers. This is a myth. Partially. There are still two factors in the game:

  1. Girls do get an X chromosome from their fathers.
  2. Boys try to copy their fathers’ strategies.

So if you want smart kids, it is still best when both parents are smart. Mother is more important though.

Smart women

Smart men get a lot of female attention, usually after graduate studies. Women understand that a smart man is more likely to be a good provider and less likely to act irrationally. Men are not generally looking for smart women. We marry smart women because they have similar interests and good communication with us. Probably not because we want our kids to be smart.

Women used to downplay their intelligence for centuries. This makes the ladies less threatening to less intelligent men and widens the pool of potential partners. Women on average are less competitive, less looking for the cutting edge opportunities, and by far less willing to sacrifice family for the sake of careers.

And then there are very smart ladies who choose to be authentic. As far as I know, they are often way smarter than their husbands. Occasionally this triggers role reversal when the kids are at school. This is probably a good thing. Smart women that find their place in the job market tend to be happier, more psychologically stable, and more interesting in conversation. [The last sentence is not based on science, but on my personal observations]


[I describe various strategies in-depth in my Teaching masterclass, and some additional ideas in Investing and Teamwork masterclasses.]

During the upbringing, rich people increase the measured IQ of their children by providing more extracurricular activities and summer courses. Something like learning an extra language does not necessarily make the child smarter. The brain gets more active during the learning stage and shrinks back afterward.

Smart people are less likely to do something really damaging, like get a divorce. Children of divorced people have more problems and earn less than their peers. When the parents argue a lot and do not divorce, there is a similar disturbing effect.

And then smart people get enough money to buy their kids a good graduate degree. I am talking about medicine, law, engineering, economy… These degrees on average are more lucrative than humanitarian or art classes. The higher salary and long-term alumni networks pay for an expensive education.

Growing as a smart child

Smart kids are usually more stressed than their peers because they have a plan and understand the costs of each mistake. Their families tend to be over-competitive. If the child jumps a grade at school, the aggregate stress shortens his life by several years. My financially most successful classmate was actually left in school for a second year, not because he was stupid but due to some relocation. We celebrate our birthdays in December. He is older than me by two years and one week.

The smart kids in school often get into all sorts of troubles:

  • They want to avoid conflict even when they have an advantage. So they are bullied.
  • The school is boring, and they tend to phase off during the lessons. The teachers often want to drug them with Ritalin or similar.
  • Some smart kids actively search for physical confrontation because they feel superior. This can be very destructive.
  • When smart kids try to do business transactions, they often are overconfident and not sufficiently educated. The results can get them in trouble with the law.
  • Even if everything else is fine, smart kids may lack friends with similar interests. Very lonely.

There was an experiment by Lewis Terman [the man who basically invented IQ tests] in 1920s with extremely talented children. Many of these children were observed for a long time, and they did not have any extraordinary achievements as grown-ups.

Parents as role models

We are the role models for our children. What they do not inherit genetically they inherit culturally. Living in a good neighborhood, working hard, and practicing smart hobbies can be very beneficial for our kids. They may resent us as teenagers, but eventually, they are likely to copy our strategies. If we can show them effective and productive strategies, they are likely to use them.

Effective strategies and wise investment of resources probably contribute to success more than innate talents. So as long as we live smart lives, our kids are likely to copy us. They will probably have different values and tactics, but the approach itself is crucial.

So I guess memetic heritage is important, along with genetic inclinations and formal upbringing.

I am not entirely sure about the role of grandparents in the education of their grandchildren. This is probably a subject for another article.

Genetic variants associated with IQ
Genetic variants associated with IQ

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