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This article, http://www.independent.co.uk/news/science/children-intelligence-iq-mother-inherit-inheritance-genetics-genes-a7345596.html?cmpid=facebook-post, suggests that children inherit intelligence from mothers, and that fathers have basically no role in that (except emotional and intuitional "intelligence" as they call it).

Since often journalists can misinterpret scientific studies, I am interested, if there are researchers in this field on this site, who can say to what extent is the statement in this article:

"Children inherit intelligence only from their mothers and not their fathers" - true?

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    $\begingroup$ Did you check the sources from the linked article? psychology-spot.blogspot.ca/2016/03/… $\endgroup$
    – Seanny123
    Oct 6, 2016 at 17:10
  • $\begingroup$ @Seanny123 had a look but not much help in answering my question $\endgroup$
    – user13903
    Oct 6, 2016 at 18:06
  • $\begingroup$ Are you referring to genetic influences of intelligence or environmental factors? $\endgroup$
    – AliceD ♦
    Oct 6, 2016 at 19:43
  • $\begingroup$ @Christiaan Not sure if you read the question carefully, of course genetics $\endgroup$
    – user13903
    Oct 7, 2016 at 5:49
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    $\begingroup$ If both your mother and father each gave you a copy of 22 books, but the 23rd book was rather different from the two parents, would it make sense to say that all the important stuff was only in that last book? Why would such an absurd system exist? All the books are equally important, but in the case of the first 22, you have two copies. So if a page was missing, you still have the whole story. Last book, not so. There is nothing more to it than that. $\endgroup$
    – user9634
    Oct 8, 2016 at 14:51

3 Answers 3

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The psychology-spot article mostly links to researches done on mice. Only three links are about human genetics. One is philosophical in nature, other two deal with mental retardation. This study says that:

"X chromosome contains a significantly higher number of genes that, when mutated, cause mental impairment".

We know that boys get their X chromosome from their mothers. Therefore, they inherit mental retardation from their mothers. But look at the terminology used in the research paper. They have not found some IQ value stored somewhere in the X chromosome. Therefore, we cannot say that mutations in the X chromosome is responsible for high intelligence as well (the study proposes such a link, but has no data to support it). There is a mystery here: if mothers carry key to mental retardation in sons, it must be a hidden trait in women because they do not exhibit that deviation as much as men.

This study takes mother's IQ into account, but it does not make any attempt to establish a direct link between the IQ of mother and son.

Conclusion: We can assume that boys inherit mental retardation from mothers (because boys get mother's X chromosome). We can not assume anything else yet, not from this study.

The following is pure speculation: Men have higher deviation in their intelligence Bell curve on both sides. If one side of it is linked to their mothers, the other side might as well be, but it probably has nothing to do with the intelligence of the mother. In my personal opinion, that article is just wishful feminist thinking. If such link was present, it would have been highlighted long ago.

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    $\begingroup$ It is perfectly simple: for anything passed on the X chromosome, females get 2 copies, so recessive harmful mutations show up far less in females than in males, who only get one X, necessarily from their mothers. It is exactly as if you had a computer where everything was stored twice, and your unlucky friend had only single storage: any failure would be a problem for him, but not for you. So, did the loss get 'inherited' from your friend's earlier computer? $\endgroup$
    – user9634
    Oct 8, 2016 at 14:44
  • $\begingroup$ Sounds like RAID storage to me. However, I don't understand what mechanism decides which part of which chromosome is bad and needs to be disabled in favor of the other. Any idea? $\endgroup$
    – Spero
    Oct 8, 2016 at 15:09
  • $\begingroup$ Most mutations don't code for properly working proteins. But if one copy makes a good version and the other makes a bad version, you are still functional. $\endgroup$
    – user9634
    Oct 8, 2016 at 21:48
  • $\begingroup$ I have started to dislike this answer of mine because it is too reactive in nature. It takes the arguments presented in the article and nitpicks about those. instead of trying to find the truth, I was trying to find faults. Please check my other answer. $\endgroup$
    – Spero
    Oct 10, 2016 at 20:09
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I am adding another answer because the previous one has already been upvoted by others. I am retreating from my previous conclusion, and I think it would be unfair to carry forward the upvotes to my current opinion.

I looked into genetics after having this conversation between me and no comprende:

...........We know that boys get their X chromosome from their mothers........... we cannot say that mutations in the X chromosome is responsible for high intelligence ........... if mothers carry key to mental retardation in sons, it must be a hidden trait........

Response:

......... females get 2 copies, so recessive harmful mutations show up far less in females.............if one copy makes a good version and the other makes a bad version, you are still functional – no comprende

The old Dominant and recessive gene theory to explain why females suffer less genetic anomalies has been challenged. The reason is X inactivation. X inactivation prevents two copies of same allele being active on an offspring and it occurs at a very early stage. The choice of which one to disable is random, but it has been observed that even distribution of inactivation in XX heterozygote is better for health. Skewed inactivation has been associated with genetic diseases like breast cancer and mental retardation.

Unfortunately, we also found this. Basically, X-skewed mothers have only 25% chance of passing on their active (those responsible for retardation) alleles to their sons.

There are two conclusive studies that resolve the puzzle by showing that X chromosome is indeed key to our general intelligence, but it is still a male trait because X chromosome is enriched for male-specific but not female-specific genes. Females do not get to enjoy most of its benefits despite being the bigger carriers of it.

In conclusion I have to agree with Jennifer's theory, but she has not made it clear what "inheriting intelligence from mother" actually means. We should not try to seek validation of our social idealism in genetics because genetics records our past. It does present some hard limits, but not this time. I did not find any ill-effect of choosing an intellectually gifted female as mating partner.

From a scientist's standpoint, it will be interesting to see (sadly we will not live to see it) how our genes cope if our mating choices start changing. There are some inefficiencies in our genes that may pose some problems, but who knows?

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  • $\begingroup$ OK, well, I guess your info is more current than mine, great! I have to agree with the intelligent person who said, "High intelligence is not as generally useful as people think it is." Not all "helpful" traits really make any significant difference in everyday life for individuals. Over geologic time, even small differences add up, but for species, not for each person, and not in a short time. You can be tall, smart and beautiful and still not have a great life. People worry too much about these things, it is more important to find ways to be happy. $\endgroup$
    – user9634
    Oct 11, 2016 at 13:43
  • $\begingroup$ @nocomprende I agree that we should not try to validate our daily lives based on higher principles, but I also think that the existence of religion speaks strongly in favor of the presence of a core drive to believe in higher principles. In the old times mysticism used to keep people happy. What now? Unfortunately this is becoming chatty. Chats are not allowed in comments. I think this topic belongs to another question currently being discussed here. $\endgroup$
    – Spero
    Oct 11, 2016 at 14:25
  • $\begingroup$ I have studied intelligence ever since, and would like to point it out that the top end of IQ does not appear to have anything to do with with genetics. We only ever inherit mental retardation. IQ potential is not static. We have proof of that in these studies: [ analisicomportamentale.com/media/… ], [ pnas.org/content/96/15/8790.short ]. $\endgroup$
    – Spero
    Apr 15, 2017 at 15:41
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Just heard a Facebook meme about this and it seems to be making another round of online. The population studies seems quite old following a cohort from 1994 to 2004. Rather than a genetic study, it seems to be more a correlational study

https://www.kidspot.com.au/parenting/child/child-development/childs-intelligence-comes-from-their-mums-science-says/news-story/273b4cffce35fb935e576c0afba0cf5e

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