Monday, May 23, 2022

A virus that increases intelligence, and what else?

 


Caterpillar infected by baculovirus, before liquefaction (Wikicommons, Williams et al. 2017)

 

Higher IQ is associated with antibodies to cytomegalovirus, but only in adults whose IQ is already above a certain level. Which is the cause, and which is the effect?



 

Cytomegalovirus (CMV) belongs to the herpes family and is spread by contact with bodily fluids. Around 45 to 100% of the population may be infected, although most hosts are unaware that they are infected. It has one of the largest genomes among human viruses, a sign perhaps of its ability to manipulate its host:

 

With millions of years of coevolution within their hosts, CMVs, like other herpesviruses, encode numerous proteins that can broadly influence the magnitude and quality of both innate and adaptive immune responses. These viral proteins include both homologues of host proteins, such as MHC class I or chemokine homologues, and proteins with little similarity to any other known proteins, such as the chemokine binding protein. Although a strong immune response is launched against CMV, these virally encoded proteins can interfere with the host's ability to efficiently recognize and clear virus, while others induce or alter specific immune responses to benefit viral replication or spread within the host. (Miller-Kittreall and Sparer 2009)

 

CMV infection at birth leads to mental retardation (Andreou et al. 2021). Recently, however, it has been shown that infection later in life can lead to higher IQ. This is one of three findings from a Norwegian study on IQ and antibodies to CMV in adults. The study showed that CMV seropositivity was significantly associated with higher IQ in men who suffered from bipolar spectrum disorders and with lower IQ in women who suffered from schizophrenia spectrum disorders. CMV seropositivity was not associated with IQ in healthy controls (Andreou et al. 2021). The study’s authors were at a loss to explain the association between CMV seropositivity and higher IQ in bipolar men, all the more so because the number of bipolar men was small, only 35.

 

An association between CMV and IQ has now been found in healthy individuals. A Czech study has shown that IQ, especially verbal IQ, is higher in people with antibodies to CMV. Moreover, the IQ advantage decreases with decreasing levels of CMV antibodies, i.e., with increasing time since the CMV infection (Chvatálova et al. 2022).

 

Why do healthy Czechs show this association but not healthy Norwegians? It’s not because the Czechs were a larger sample. In fact, the Czech sample had 283 healthy individuals, and the Norwegian sample 474. The two samples did differ, however, in educational attainment. The Czechs were biology students at a university in Prague, whereas the Norwegians were randomly recruited from the Norwegian population register. The latter were also described as “Caucasians” living in Oslo. Oslo’s population is almost one third of immigrant origin, with Pakistanis forming the largest immigrant group. There are also large numbers of people from Sri Lanka, Turkey, Morocco, and Iraq (Wikipedia 2022). 

 

The last point would not be problematic if cognitive evolution had ended long ago among the common ancestors of Europeans, Middle Easterners, and South Asians. There is mounting evidence, however, for cognitive evolution in recent times. Ashkenazi Jews seem to have gained their cognitive advantage during the past 1,000 or so years, and the same seems to be true for the Parsis (Cochran et al. 2006; Dunkel et al. 2019; Frost 2021). There is even evidence for significant cognitive evolution in communities that are not normally thought of as ethnic groups, such as French Canadians in regions where British and American traders were historically few in number (Frost 2012).

 

Why does CMV seropositivity correlate with higher IQ?

 

The authors of the Czech study suggest that more intelligent people have more social contacts and are thus more likely to catch the virus: “we suggest that more intelligent subjects who have more social and sexual contacts—CMV is transmitted by close contacts, e.g. by kissing—might have a higher risk of encountering a CMV infection.” Yet there is no evidence that smarter people are more extraverted. In fact, they tend to be loners, if only because they have fewer people of their intellectual level to hang out with. The academic consensus seems to be that neither introversion nor extraversion correlates with intelligence (Saklofske and Kostura 1990).

 

Could the arrow of causality run in the other direction? Is it possible that CMV makes its host smarter? The authors reject that explanation because congenital CMV infection reduces intelligence. But maybe the effect is different in adults.

 

If CMV does increase the intelligence of adult hosts, the effect would be confined to those whose IQ is already above a certain level. The above two studies showed a significant increase only among university students, and not in a more mixed population with varying levels of educational attainment. But why did the latter study show significantly higher IQ in men with bipolar disorders and significantly lower IQ in women with schizophrenia? For the answer, we can turn to the results of a recent genome-wide association study: most of the alleles for schizophrenia are associated with lower intelligence, and most of the alleles for bipolar disorder are associated with higher intelligence (Smeland et al. 2020). Those results are partially confirmed by the findings of a prospective cohort study: “at least in men, high intelligence may indeed be a risk factor for bipolar disorder, but only in the minority of cases who have the disorder in a pure form with no psychiatric comorbidity” (Gale et al. 2013).

 

Behavior alteration?

 

Why would a virus try to make its host smarter? What would it gain? Perhaps the increase in intelligence is a side-effect. Perhaps the virus is trying to improve its chances of spreading to new hosts by altering the behavior of its current host (Cochran et al. 2000; Frost 2020).

 

Although behavior is more often altered by larger and more complex pathogens, particularly fungi, there are many viruses that engage in behavior alteration. For example, viruses from the baculoviridae family will infect a caterpillar and make it hyperactive to spread their viral progeny over a wider area. Or the caterpillar will be made to climb to the top of a plant and dissolve itself through overproduction of enzymes, thus becoming a mass of tasty goo for ingestion by potential hosts (Han et al. 2015; Williams et al. 2017). Rabies is another behavior-altering virus: it makes its host more aggressive and thus more likely to bite potential hosts.

 

Although CMV infects a wide range of people, it seems to target a smaller subgroup for behavior alteration, i.e., individuals with intelligence above a certain threshold, and men more than women. If we look at the epidemiological data, we see that male homosexuals are especially susceptible. A study at a venereal disease clinic found that antibodies to CMV were present in 94% of the male homosexual patients and 54% of the male heterosexual patients. “The data suggest that sexual transmission is an important mode of spread of CMV among adults and that homosexual men are at greater risk for CMV infections than are heterosexual men” (Drew et al. 1981). Another study has identified passive anal sex as the most effective means of transmission: “Of seven sexual practices investigated, only passive anal-genital intercourse correlated with the acquisition of cytomegalovirus infection (p =0.008)” (Mintz et al. 1983).

 

Which is the cause and which is the effect? Does passive anal sex facilitate CMV infection? Or does CMV infection facilitate the desire for passive anal sex? The answer may be ‘yes’ to both questions. Sometimes ‘the cause’ and ‘the effect’ are two sides of the same coin.

 

This virus may indeed be the ‘gay germ’ that Greg Cochran has written about. Or one of them. Male homosexuality probably has several causes, and the microbial cause probably involves more than one pathogen.

 

 

References

 

Andreou, D., K.N. Jørgensen, L.A. Wortinger, K. Engen, A. Vaskinn, T. Ueland, R.H. Yolken, O.A. Andreassen, and I. Agartz. (2021). Cytomegalovirus infection and IQ in patients with severe mental illness and healthy individuals. Psychiatry Research 300:113929. https://doi.org/10.1016/j.psychres.2021.113929  

 

Chvatálová, V., B. Šebánková, H. Hrbáčková, P. Tureček, L. Příplatová, and J. Flegr. (2022). Differences in cognitive performance between cytomegalovirus-infected and cytomegalovirus-free students. PsyArXiv, 5 May 2022. https://doi.org/10.31234/osf.io/jbvky  

 

Cochran, G.M., P.W. Ewald, and K.D. Cochran. (2000). Infectious Causation of Disease: An Evolutionary Perspective. Perspectives in Biology and Medicine 43 (3): 406-48.

https://doi.org/10.1353/pbm.2000.0016  

 

Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science 38: 659-693, https://doi.org/10.1017/S0021932005027069  

 

Drew, W.L., L. Mintz, R.C. Miner, M. Sands, and B. Ketterer. (1981). Prevalence of Cytomegalovirus Infection in Homosexual Men. The Journal of Infectious Diseases 143(2): 188–192. https://doi.org/10.1093/infdis/143.2.188

 

Dunkel, C.S., M.A. Woodley of Menie, J. Pallesen, and E.O.W. Kirkegaard. (2019). Polygenic scores mediate the Jewish phenotypic advantage in educational attainment and cognitive ability compared with Catholics and Lutherans. Evolutionary Behavioral Sciences 13(4): 366-375. https://doi.org/10.1037/ebs0000158  

 

Frost, P. (2012). Tay-Sachs and French Canadians: A case of gene-culture co-evolution? Advances in Anthropology 2(3): 132-138. http://dx.doi.org/10.4236/aa.2012.23016  

 

Frost, P. (2020). Are Fungal Pathogens Manipulating Human Behavior? Perspectives in Biology and Medicine 63(4): 591-601. https://doi.org/10.1353/pbm.2020.0059   

 

Frost, P. (2021). Commentary on Fuerst et al: Do Human Populations Differ in Their Mental Characteristics? Mankind Quarterly 62(2). http://doi.org/10.46469/mq.2021.62.2.9  

 

Gale, C., G. Batty, A. McIntosh. et al. (2013). Is bipolar disorder more common in highly intelligent people? A cohort study of a million men. Molecular Psychiatry 18: 190–194. https://doi.org/10.1038/mp.2012.26  

 

Han, Y., S. van Houte, G.R. Drees, M.M. van Oers, and V.I. Ros. (2015). Parasitic Manipulation of Host Behaviour: Baculovirus SeMNPV EGT Facilitates Tree-Top Disease in Spodoptera exigua Larvae by Extending the Time to Death. Insects 6(3): 716–731. https://doi.org/10.3390/insects6030716  

 

Miller-Kittrell, M., and T.E. Sparer. (2009). Feeling manipulated: cytomegalovirus immune manipulation. Virology Journal 6: 4 (2009). https://doi.org/10.1186/1743-422X-6-4  

 

Mintz, L., W.L. Drew, R.C. Miner, and E.H. Braff. (1983). Cytomegalovirus infections in homosexual men. An epidemiological study. Annals of Internal Medicine 99(3):326-9. https://doi.org/10.7326/0003-4819-99-3-326

 

Saklofske, D. H., and D.D. Kostura. (1990). Extraversion-introversion and intelligence. Personality and Individual Differences 11(6): 547-551. https://doi.org/10.1016/0191-8869(90)90036-Q  

 

Smeland, O.B., S. Bahrami, O. Frei, A. Shadrin, K. O'Connell, J. Savage, K. Watanabe, F. Krull, F. Bettella, N.E. Steen, T. Ueland, D. Posthuma, S. Djurovic, A.M. Dale, and O.A. Andreassen. (2020). Genome-wide analysis reveals extensive genetic overlap between schizophrenia, bipolar disorder, and intelligence. Molecular Psychiatry 25(4):844-853. https://doi.org/10.1038/s41380-018-0332-x  

 

Williams, T., C. Virto, R. Murillo, and P. Caballero. (2017). Covert Infection of Insects by Baculoviruses. Frontiers in Microbiology 17(8): 1337. https://doi.org/10.3389/fmicb.2017.01337

 

Wikipedia (2022). Oslo – Demographics. https://en.wikipedia.org/wiki/Oslo#Demographics

20 comments:

Anonymous said...

One tiny study from a college is basically junk--range restricted and subject to Simpson's paradox. Perhaps the students who had CMV and still got into college had to have higher IQ to offset its negative impact on energy levels (the virus usually constitutes 10-40% of immune load).

Extraordinarily unlikely a virus everyone gets is the gay gene. As we've seen with monkeypox, men who have sex with lots of men pass around a LOT of viruses.

Sodomita said...

"Extraordinarily unlikely a virus everyone gets is the gay gene. As we've seen with monkeypox, men who have sex with lots of men pass around a LOT of viruses."

Pau no teu cu, seu filho da puta! - dick in your ass, you son of a bitch!

You American HBDs are a bunch of stupid homophobes! I understand much more about human biodiversity than 99% of heterosexuals in my country. You are a bunch of intellectual lazybones.

Santocool said...

''Yet there is no evidence that smarter people are more extraverted. In fact, they tend to be loners, if only because they have fewer people of their intellectual level to hang out with. The academic consensus seems to be that neither introversion nor extraversion correlates with intelligence (Saklofske and Kostura 1990).''

When it doesn't suit you, ''there isn't enough evidence.'' When it suits you, even when there is no evidence, you assume it does.

Difficult to give credibility to you.

What you need to understand is that IQ is not intelligence. So there are different profiles and types of intelligences, which do not cancel out the relevance of the tests. This is the plural reality of intelligence. It is not so complex that you cannot understand.

There is evidence showing that humanities students are much more likely to lose virginity before a certain age than STEM students.

In one area where the ability to communicate is one of the most important, introversion tends to be a problem.

There are many individuals, more intelligent than the average, who have strong intellectual leanings toward the humanities.






''You American HBDs are a bunch of stupid homophobes! I understand much more about human biodiversity than 99% of heterosexuals in my country. You are a bunch of intellectual lazybones.''


Sodomita,

[he's not me]

The vast majority of heterosexuals are more concerned with

sports;

sex;

religion;

talk about politics in stupid ways.

It even looks like a kind of syndrome...

I find it funny how cult HBDs don't mind talking about severe disabilities in a number of pertinent areas that affect large fractions of straight people, one of their adored groups.

This is the difference between science and a cult and passing as such.

Santocool said...

"Extraordinarily unlikely a virus everyone gets is the gay gene. As we've seen with monkeypox, men who have sex with lots of men pass around a LOT of viruses."

Of course not. If it were true, it would be like a contagious disease that is typically transmitted.

My guess is that some gay Europeans with money to go sex tourism in Africa decided to have fun there and ended up contaminating themselves with a native man's virus.

As the incubation of this virus is prolonged, they returned to Europe and continued to ''havefun'' and spread the virus to many.

As many do not present symptoms or not soon after being contaminated, they were transmitted to others.

But I don't think the virus has mutated and become venereally transmissible, it's just that it's extremely easy for any variably contagious virus to spread through a community of extremely promiscuous individuals, which I include, as unfortunately I'm not in a solidly monogamous relationship, as I wanted.


"Extraordinarily unlikely a virus everyone gets is the gay gene. As we've seen with monkeypox, men who have sex with lots of men pass around a LOT of viruses."


But the vast majority of these ''viruses'' must be domestic to human biology.

It is no different to say that you pass many viruses or microorganisms to your wife daily.

Santocool said...


First, a study in a venereal disease clinic....

What do you expect to find there??

How is it possible that I was attracted to the same sex as a child without ever having had sexual contact before?

I am part of the group of gay/Bisexual men who are the youngest of three male brothers and through my maternal line, there is an incidence of mental disorders in two uncles.

The whole premise of the "gay pathogen hypothesis" is based on the misguided idea that "evolutionarily, it would not be possible for sexual diversity to be transmitted like other common traits, because it has no PRIMARY advantage."

Well, blue eyes don't have any primary advantage either, because it doesn't matter what color your eyes as long as they work.

However, every evolutionary process NEEDS a minimum load of biological diversity to sthrive, especially for multicellular species, otherwise it is as if you invested in a single evolutionary strategy, very risky, as you may have to change trajectory. It's always important to have some diversity.

So, sexual diversity does not need to be directly transmitted, because it is part of this package of biological diversity that the human species carries for thousands of years, and based on its existence in the vast majority of human populations, it seems that it has existed among us for a long time.

I still believe this is due to personality* diversity or variation.

*reactive adaptational strategy.

Looking closely at the supremacy of heterosexual men today, I would say that, if that wasn't enough: centuries of mindless wars, psychopaths taking turns in power, absurd social inequalities or parasitism, we are, in a very turbulent way, reaching an advanced level of civilization, but without elementary aspects, such as social and moral, we have advanced very little.


''They acquired ANTIBODIES...''

You mean their bodies have developed defenses to fight the transmission of the virus, right??

All people who were infected with the corona virus and didn't die, do they have viruses inside the body or antibodies??

54% of heterosexual patients are very...

They got infected with the gay virus and became gay???



In clinical terms, sexual diversity does not meet all the criteria to be determined as a spectrum of mental or organic disorders.

It also does not meet criteria to be categorized as an absolutely balanced spectrum of conditions, and therefore falls into a gray zone of classification, regardless of its etiology.

As I always say when dealing with the hypothesis of the gay pathogen, we must get used to seeing ourselves as a ''walking environments'' where multiple microorganisms variably adapted and co-operative with their old hosts.

I do not doubt if human sexuality itself, including our impetus for recreational sex, cannot be caused or helped by microorganisms either.

Santocool said...

Either way, that would mean they are NOT "sick".

LOL.

Santocool said...

Can a virus make a someone's brain more similar to his opposite sex, like alter all his brain structures??

Santocool said...

''The academic consensus seems to be that neither introversion nor extraversion correlates with intelligence''

This means that there is no significant predominance of one of these traits in gifted people...

https://www.studyfinds.org/parasite-makes-more-attractive/

''The parasite may actually change how your face looks
While previous studies on T. gondii suggest that the parasite leads to higher testosterone levels in men, others suspect that the parasite manipulates chemicals in a host’s body — including neurotransmitters and hormones''

''Manipulating a host’s “phenotype,” Borráz-León says, can lead to far-reaching changing — including how a person actually looks physically.

“Some sexually transmitted parasites, such as T. gondii, may produce changes in the appearance and behavior of the human host, either as a by-product of the infection or as the result of the manipulation of the parasite to increase its spread to new hosts,” the researchers write in their study.

In an experiment including 35 college students (22 men, 13 women) infected with T. gondii and 178 students not carrying the parasite, researchers looked at how symmetrical their facial features were. The team explains that fluctuating asymmetry is a measure of how different the features in your face are. Studies have linked having more symmetry in your face (lowers levels of asymmetry) to better health, stronger genes, and being more attractive to others.


Results show that Toxoplasma-infected participants had lower levels of fluctuating asymmetry than healthy college students. Additionally, young women carrying the parasite had a lower body mass index than their peers. These women also rated themselves as more attractive and reported that they had more sexual partners.''

Santocool said...

''The academic consensus seems to be that neither introversion nor extraversion correlates with intelligence''

[This means that there is no significant predominance of one of these traits in gifted people...]

like,

The gifted population can be 50/50% extroverted/introverted.

Peter Frost said...

Anon,

The study had 283 participants. That's a robust sample size. Your alternative explanation is interesting but not applicable. The infected participants are described as having a "latent" infection, i.e., asymptomatic.

Santocool and Sodomita,

Looks like I struck a raw nerve. Do you agree that every effect has a cause? (I hope so). Do you feel that a microbial cause is somehow less "noble" than a genetic cause or a purely social cause? If so, why?

What do I expect to find in a venereal disease clinic? I expect to find people (I don't expect to find monsters, if that's what you mean).

You ask: "How is it possible that I was attracted to the same sex as a child without ever having had sexual contact before?" Through contact with saliva. It's not difficult.

FWIW, I don't believe that male homosexuality has a single cause. But I'm interested in the possibility of a microbial cause. If microbes can manipulate the sexual behavior of nonhuman animals, why would humans be exempt? What makes us special?

Santocool said...

I think you need ask for yourself. Expecting a post from you talking about the correlation between facial attractiveness and toxoplasma infection... among heterossexual from this article.

Are you naive enough to think it will not be used against LGBT people?? I really doubt. And your "i was a marxist activist in university and now i'm not on the left because they no longer defend working class" don't convince me and i bet no one who have a normal os controllable levels of naivety... even saying "i was marxist..." these people who are mostly justifying genocidal aggression against Ukraine?? why not just say "i'm a psycho or sociopath who like to play the scientist about very controversial themes that very likely will be/already are being used to spread even more hate against many innocent people and i don't care"??

Why do you expect to find in a place which most people already have contacted with someone with venereal disease or were being treated from it??

Your mental jumping is interesting from "they had an antibodies produced by body to fight infection" to "they have/had a PATHOGEN that changed totally their brains"

Having a PATHOGEN or PARASITE in my brain changing my behavior doesn't look a noble thing don't you?? Or at least for the crowd of sub evolved people who think i'm sinner, criminal or something else because my bissexual inclination.

I don't think you understood my question. Your answer was very silly.


Santocool said...

Male homossexuality.

What make you think only male gays or bis who are supposedly infected by a "pathogen" that change their sexual inclination??

Again. Can play a scientist and not a polemizer who serve to right wing psychos, analyse levels of toxoplasma or another one in children who display nonheterossexual behaviors and compare with heterossexual children; look to sperm of homossexual and bissexual men and compare with heterossexual, preferencially searching for virgin and/or young bi and gay men and hetero. That's not difficult. And whatever the findings, trying to be ETHICAL. I should not be teaching foi how to be a good scientist but maybe is also not in your control...

Santocool said...

Finally, humans are very special, not totally different but very special, for good and bad. I'm not seeing any other species trying to communicate with extraterrestrial civilizations. Humans are different enough that 90% of "animal experiments" fail to replicate

Santocool said...

How do you explain the 9% of cases, which I include, of birth order and homosexuality in families with only male children??

Santocool said...

''How do you explain the 9% of cases''

Two studies estimated that between 15% and 29% of gay men owe their sexual orientation to this effect, but noted that the number may be higher, as previous miscarriages and abortions may have exposed their mothers to Y-linked antigens.

Anonymous said...

mister santocool is a living proof that unpleasant truth may damage your intelligence :))
certainly infected even in the womb of his mother by a number of the most vicious germs of all kinds.
stay cool, my saint: if being gay is kind of an incurable desease, this does not imply you would be considered a less valuable member of society. quite the contrary: you would need more protection and respect than healthy heteros.
and if that infection leads to increased intelligence (aka higher IQ in tests) - the better!

Peter Frost said...

Santocool,

We all have "parasites" living within our bodies. Most of them are commensals that form an essential part of us. I understand you have a prejudice against microbes, but many if not most of them are necessary for our existence.

I'm not trying to be cute. We have coevolved in many interesting ways with other forms of life, including microbial life.

I was never really a Marxist. In French, I was, and still am, a "Marxisant." I believe that both Marx and Engels had valuable insights into the nature of society and history, particularly the nature of relations between capital and labor.

As for Ukraine, I am saddened by what is happening, particularly the loss of life. It's possible to replace infrastructure, but human life is not replaceable. Unfortunately, war is sometimes inevitable.

This is not a war between Ukraine and Russia. It's a proxy war: NATO provides the arms and ammunition, and Ukraine provides the cannon fodder. And let's not be mistaken. NATO hasn't been a defensive alliance for more than two decades. It has mutated into an offensive alliance that needs to be reined in.

For the sake of world peace, I hope Russia gives NATO a bloody nose.

Santocool said...

''We all have "parasites" living within our bodies. Most of them are commensals that form an essential part of us. I understand you have a prejudice against microbes, but many if not most of them are necessary for our existence.''

With this answer I can only conclude that you are another ''HBD'' clown.

You should be ashamed; be responsible for your actions, but for a psychopathic subhuman, that doesn't exist.

I find it funny that, regarding some of my most important questions, you don't even have a little elderly whitetrash joke.
Such as the ''birth order'' factor, one of the most interesting and consistent findings about the possible etiology of homosexuality, especially in men.

If you were a scientist, in fact, you should not overlook this factor.

I have the ABSOLUTE right to participate in this conversation. In fact, I think those who shouldn't participate are moral retards like you and that Jewish rat.

Santocool said...

''mister santocool is a living proof that unpleasant truth may damage your intelligence :))
certainly infected even in the womb of his mother by a number of the most vicious germs of all kinds.
stay cool, my saint: if being gay is kind of an incurable desease, this does not imply you would be considered a less valuable member of society. quite the contrary: you would need more protection and respect than healthy heteros.
and if that infection leads to increased intelligence (aka higher IQ in tests) - the better!''

Being ''protected'' by ''conservatives'' is the last thing I want in my life. I actually would like to exterminate the most dangerous, and domesticate the idiots.

We all have bacteria and viruses in our bodies. In fact, we seem to have more of them than cells.

We are walking environments, hosts of microorganisms that have co-evolved for millions of years since humans didn't even exist.

I think this possibility is fantastic.

But to say that my sexual inclination is a disease is a big mistake and that goes against any valid concept of disease definition.

Nor could down syndrome, given its relative symptomatic stability, be considered a disease, even without sexual attraction.

Either way, an infection presupposes a certain level of randomness, and what we see here is a case in which there are characteristic patterns and results that run counter to the idea of infection.

And how to explain those homosexuals who are extremely androgynous. In their case, it's not just a neurological difference but also a noticeable difference in facial and physical terms.

In general, homosexuals tend to display several physical characteristics that are statistically different from heterosexuals.

These facts work against the idea of infection altering behavior, as infection should alter the person's phenotype and maintain it by some unknown or unlikely mechanism...

Has the ''gay pathogen'' made me shorter than my brothers?

;)

Mike Dammann said...

Not to forget:
Different increases based on Rh factor:
https://www.rhesusnegative.net/staynegative/what-is-your-iq-and-do-you-have-toxoplasmosis/