Nor Breeding Their Best

Now that we have established that immigration is not much good, let’s take a look at another component undergirding our transition to Idiocracy – the differential fertility rates of different IQ groups.

This is a highly contentious topic, and not just on account of the usual political kurfuffles, but also on real disagreements as to its actual extent. Psychologists such as Richard Lynn, Edward Dutton, and Michael Woodley are pessimistic (Woodley 2014; Dutton et al. 2016). OTOH, JayMan has argued based on WORDSUM analysis that “Idiocracy can Wait.” This topic is extra difficult because you also have to disentangle the dysgenics trend from the Flynn effect that has raised IQs in the developed by about 10 points during the 20th century.

The PISA Data Explorer is truly an invaluable tool for bringing the light of cold, hard facts on these issues.

While playing around with it, I noticed you can select the variable “same age siblings,” which ranges from zero to ten. Zero siblings implies, of course, that the student in question is an only child; by definition, the survey excludes entirely the childless portion of the population, which is also its brightest. Data only exists for the Mathematics part of PISA 2000, but it is more than enough to get an idea of the general trend – and as you might expect, it’s not a very good one.

I calculated the “slope” in terms of PISA-adjusted IQ points lost per additional sibling for the first four siblings (in practice, since TFR <<6 for all countries in PISA 2000, the IQ of children from even larger families won’t have much of an effect). See the table at the bottom of this post.

Here are some general points to take away:

(1) Indonesia is the only country, at least as judged from the Math portion of PISA 2000, that has eugenic fertility patterns (since its a developing country with a TFR = c.2.5, we can be pretty sure that childlessness will not impact these statistics down by very much since its simply very rare). Second is Thailand. Both are lower-middle income Asian countries that only escaped the Malthusian trap within living memory and are in the middle stages of the demographic transition. (That said, in PISA 2015, coverage of the 15 year old population was not great in either country – 68% in Indonesia, 71% in Thailand – and assuming that was also generally true in 2000, those not turning up are sure to be less bright and will probably come from more rural, bigger families).

[Epistemic status: Speculative]. However, despite also being within the middle-income brackets, the Latin American countries have moderately dysgenic fertility patterns. I wonder if this could explain Steve Sailer’s observation that Latin American countries seem to have smaller smart fractions than Middle Eastern ones, despite similar average IQs. Maybe their European and, critically, Europeanized, upper classes have simply failed to reproduce in the last couple of generations?

(2) The East Asian and European Nordic states have more eugenic fertility patterns. The European Mediterranean – Greece, Italy, Romania, Portugal, Bulgaria – has some of the worst. France, Spain, Brazil, the UK, Germany, Poland, Russia, and the US all cluster close to each other (though American White fertility is probably more eugenic, perhaps around Australia’s and Canada’s level, since minority and especially Black fertility patterns are known to be highly dysgenic even according to JayMan’s optimistic analysis).

(3) The rate of childlessness is considerably lower, at around 10%, in the ex-Soviet bloc and East-Central Europe than in Western Europe and the US.


This means that their real figures will get a modest boost relative to those of Western Europe, since not as big a percentage of the professional class are getting cut out entirely.

(4) You can’t precisely quantify the dysgenic impact from this with any exactitude, since you’ll also need to combine it far more detailed fertility data.

That data does exist, at least for many of the OECD countries and Russia, so its doable, but it would be a pretty big project.

(5) Eyeballing it there seems to be a moderate degree of correlation with commenter Cicerone’s country estimates of dysgenic fertility extracted from fertility data of educational classes.

IQ vs. #Siblings

Country #0 #1 #2 #3 #4 b
Indonesia 78 82 83 81 80 0.37
Thailand 88 91 90 89 88 -0.16
Japan 103 104 103 103 102 -0.48
Ireland 104 106 106 104 102 -0.51
Iceland 103 102 101 101 100 -0.59
Denmark 99 101 100 98 97 -0.70
Finland 108 108 107 107 105 -0.70
Norway 101 102 102 101 98 -0.71
Sweden 102 104 104 102 99 -0.83
Korea 103 104 103 102 100 -0.88
Chile 87 88 88 85 84 -0.93
Israel 95 96 97 94 91 -0.94
Canada 106 106 105 105 102 -1.07
New Zealand 103 107 106 104 99 -1.13
Australia 105 106 105 102 101 -1.13
Peru 75 80 79 74 71 -1.27
Mexico 89 94 92 88 85 -1.37
Switzerland 99 100 100 98 93 -1.42
Austria 100 100 99 97 93 -1.69
Latvia 95 96 94 91 89 -1.70
Albania 76 81 79 75 70 -1.83
France 102 102 102 98 95 -1.86
Spain 101 100 98 96 94 -1.88
Brazil 87 88 86 83 80 -1.93
United Kingdom 107 106 104 102 99 -1.93
Germany 99 100 97 92 93 -1.93
Poland 101 99 97 92 94 -1.95
Russia 98 96 92 90 90 -2.01
United States 103 105 102 99 96 -2.01
Luxembourg 94 93 91 89 85 -2.17
Hong Kong 106 105 103 101 96 -2.41
Belgium 103 104 102 99 93 -2.45
Czechia 101 101 98 95 91 -2.63
Greece 101 97 95 93 90 -2.66
Hungary 99 99 96 92 89 -2.75
FYROM 80 84 78 72 72 -2.84
Romania 93 92 88 85 81 -3.03
Italy 102 99 96 94 89 -3.03
Bulgaria 92 91 85 83 80 -3.19
Portugal 100 97 94 92 87 -3.20
OECD Average 101 101 99 97 95 -1.57
Total Average 97 98 96 94 91 -1.64


Anatoly Karlin is a transhumanist interested in psychometrics, life extension, UBI, crypto/network states, X risks, and ushering in the Biosingularity.


Inventor of Idiot’s Limbo, the Katechon Hypothesis, and Elite Human Capital.


Apart from writing booksreviewstravel writing, and sundry blogging, I Tweet at @powerfultakes and run a Substack newsletter.


  1. Bulgaria, Romania, Macedonia (FYROM), Hungary all have large gypsy populations which skew the results due to large gypsy families & smaller Slav/Latin/Magyar families

  2. I calculated the “slope” in terms of PISA-adjusted IQ points lost per additional sibling for the first four siblings (in practice, since TFR <<6 for all countries in PISA 2000, the IQ of children from even larger families won’t have much of an effect). See the table at the bottom of this post.

    I am still wondering if different fertility rates in the countries in question skew your results a bit. In low fertility countries like Germany, the difference between 0, 1 and 2 siblings matter much more than that between 2 and 3 for example. If there are statistics on the percentages or distribution, one can refine the b measure.

    Anyway, it’s interesting how in many countries, children with one sibling are slightly more intelligent than single children. This speaks for a strong two-child norm in these countries, to which more educated people are more likely to cling.


    The finding that WHR correlates both with fertility and with higher IQ as conventionally measured goes part of the way towards explaining why intelligence may not have been falling in Western societies in the way in which luminaries like Russell and Fisher feared it would,…
    Exactly the same insight explains the paradox of the high fecundity of seemingly lower IQ women. If tests like the RME were included, the results would underscore the link between female fertility and mentalistic intelligence revealed by WHR. … This means that just because a woman’s measured IQ appears to be low, that of her children need not—especially if cultural factors like those underlying the Flynn effect impinge on them more than they do on her. In other words, the diametric model allows for trade-offs, not just between mentalistic and mechanistic intelligence in.. differences between parents and their children, despite the very high heritability of intelligence

  4. large is an understatement. In 2017, 49% of all first graders in Bulgaria will have romani (gypsy) as their first languages and this is according to official data from the ministry of education. There is a huge problem in this part of the world that in 10 years will transfer into all kind of problems. Avg IQ of romany group in East Europe is 78 and their ability to maintain any of the political and economic features of the modernity is doubtful. There is a creeping disaster coming. Or full collapse. It is certain and unavoidable.

  5. Philip Owen says

    Around 2000, I remember reading a study on British women who had graduated in 1970. It had been set up in 1970 so experimental construction was sound. The study group was preselected.

    A third of women graduates had never married and half of those who had married had not had children. So at the top of the system for examinocracy, 2/3 women did not reproduce. Of course, in those days, teachers, nurses and art & design students went to specialist institutions and were not considered University graduates. So did lower level engineers and accountants, then still mostly male. Only 5% of the population went to University and less than a third were women.

    So at most 5 out of 300 women studied at University and 2 out of 3 of them were childess at 50. So the top 1% of women with examination passing skills did not reproduce. Most women at my University studied English, other Languages, Geography, Psychology, Law and Social Administration. A significant minority in Maths and the Sciences. 4 out of 35 did Engineering Science with me which was about the same as the national ratio today – 9%. 3 of those were the daughters of engineers. I suspect that many women with a technical/practical bent did nursing, by then no longer a profession for spinsters.

    So there was a real but small leak right at the very top of the examination passing ability range. OTOH there was some evidence that richer families had more children in the 70’s and 80’s before stay at home motherhood became socially shameful so a eugenic trend may still have been in place. The purchasing power of relative wages for the under 35’s being much lower then than now with a statutory minimum wage. At the time the average age of marriage for a woman was 21 (and many in my school married at 16).

  6. Almost Missouri says

    “American White fertility is probably more eugenic, perhaps around Australia’s and Canada’s level, since minority and especially Black fertility patterns are known to be highly dysgenic even according to JayMan’s optimistic analysis”

    So, in other words, the so-called “achievement gap” in the US will continue to worsen in spite of ever more resources being thrown into it?

  7. I love this theory. I just wrote a piece on Lassek and Gaulin’s WHR/intelligence paper last night. I’m a nutritionist/personal trainer so I know the positive effects of omega-3s and DHA and how they’re imperative for brain development both in-vitro as well as postnatally into infancy.

    It’s also pretty much established that one’s IQ is inherited from their mother. The WHR/DHA/omega-3 theory shows great explanatory power for that, in my opinion.

  8. Wow that is pretty bad (if true). Is there a source for this? Wiki gives 5% of the Bulgarian population as gypsies as of the 2001 census. They are much more fertile than average, but rising to near 50% amongst the youngest age cohorts still seems highly unlikely (also many would have presumably emigrated after Bulgaria entered the EU).

  9. Any ideas as to why fertility appears so dysgenic in Poland and Russia? Is this actually the case?

  10. Help! The smart folks do not want to breed more tax slaves, wage slaves and cannon fodder for the system, what could possibly went wrong?

  11. No. You are misinterpreting his statement. He did not say that there is a change in white American fertility patterns, only that the white pattern is probably more eugenic than the US as a whole.

  12. Almost Missouri says

    Right, if there are two groups with a certain achievement gap, and the group that is ahead also has more eugenic reproduction, then the achievement gap between the two groups should grow over the generations.

    Or are you suggesting that the difference in eugenics is the only thing holding the two groups’ achievements apart in the first place?

  13. Anonymous Nephew says

    “had more children in the 70′s and 80′s before stay at home motherhood became socially shameful”

    Socially shameful or practically unaffordable? In my experience stay at home (non-single) mums tend to be well-educated types with (crucially) well-paid husbands. It’s almost a status symbol.

    In huge areas of Britain it’s just not possible to raise a family and buy a house on an average single wage. I guess you could still perhaps do it in the Valleys or some parts of the North, but that’s where there are few decently paid jobs.

    40/50 years back a father who worked in a factory could buy a house and have a non-working wife. Not so now, unless he’s finance director.

  14. I do not know much about Bulgaria, but Bulgaria has more Gypsies than Hungary. Hungary has about 8-10% Gypsies, while the official statistics based on self-report is something like 3%. Considering their higher fertility rate one can guess 20-25% gypsies among schoolchildren in Hungary.