Race differences in fertility are partially genetic too
In the past, the heritability of fertility was fairly low due to the lack of contraception and higher levels of child mortality, but now the correlation between parents and children in fertility has increased, as self-selection corresponds more closely to realized fertility in a modern environment.
Given that adoptive siblings correlate at 0.1 in fertility, and that biological/DZ siblings correlate at .2-.25, the true heritability of fertility is about 20-30%; anything above that is likely just an overestimate.
One could argue that, as variance in fertility between individuals is not that genetic, that this should be expected to be the case for races to. This is sophistry; consider that the heritability of intelligence is about 50-75%, and that the heritability of income is about 30-50%, but that intelligence explains the entire difference in income between Blacks and Whites. If race differences in less heritable traits are downstream from more heritable traits, then the heritability of the between race differences in traits will be higher than the heritability between individuals.
There are two ways race differences in fertility can be genetic: extended phenotypes, where genetic differences between groups cause them to have macro-level structural and cultural differences, and differences in individual phenotypes, where the genetic differences between groups cause them to act in a different way on an individual level.
On the extended-phenotypic level, the elephant in the room is IQ. Intelligent nations tend to develop modern economies, which encourage their citizens to plan their fertility with birth control and education. At the moment, the average IQ of a country and its TFR correlates at -.74:
Low IQ countries can also adopt the low fertility extended phenotype, as can be seen by the fertility of Puerto Rico, Moldova, and some small African islands. It is, however, less likely that they adopt the phenotype over time
On the individual level, intelligence and social class typically have a small, negative correlation with fertility, though this varies substantially by region and country. This is less true for recent cohorts, and in some countries the relationship has flipped in the opposite direction.
In terms of personality, within both sexes, extraverted and close minded people had more children, and within women, conscientious people had less children.
Roughly the same results replicated within Norway, though neurotic Norweigans tended to have slightly less children.
Accordingly, East Asians, who are intelligent, conscientious and introverted, typically have fewer children than Blacks or Whites when they occupy the same countries. The median East Asian country has a fertility of 0.99, while the median fertility of East Asians abroad is 1.23, only 0.2 higher.
This analysis is biased by the fact that emigrants are not representative of their national countries and immigrants frequently breed with natives. In the latter case, if immigrants pair up with the natives, their ancestral predisposition to fertility will be intermediate. In practice, the fertility rates by interracial couple do not support the hereditarian hypothesis, likely due to the fact that interracial couples are self-selected. Oddly enough, White women who date outside their race are more likely to have a child in comparison to White men — I’m not exactly sure why this is.
Besides the fact that East Asians have unusually low levels of fertility, Central Asians have unusually high levels of fertility within their host countries which have refused to drop ever since the start of the 21st century.
The cause of this is not some kind of environmental contaminant or state policy; the fertility of the ethnic Russians within these countries is only about 0.2 points higher than it was in Russia in the same time period.
Besides the outliers in Asia, race differences in fertility independent of the extended phenotype effect are small and inconsistent in direction. Hispanics and Arabs typically have had high fertility rates, but their ferility has been decreasing as of late, as the fertility of non-western immigrants typically reverts back to the native mean within one generation. This was the case in Denmark, and to a lesser extent, the United States:
Norway has good data on fertility by country of origin due to the way they keep their data. For the first generation of immigrants, their fertility is largely reflective of the rates of their original country, for the second, they regress heavily towards the mean in most cases; though this is less true for larger groups.
A similar study was conducted for second-generation women sampled in the 1970 US Census, where the country of origin of their fathers was used as a proxy for their ancestry, and it was tested whether a father’s country of origin predicted the fertility of their daughters in the United States. There was an effect, though it was small: an increase of one unit in TFR predicted an increase of 0.2 children within the daughters.
This was the rank order by country:
The hajnal women, Chinese, Mexicans Filipinas, and the French/Irish were at the top and Swedes, Finns, and Southern Europeans were at the bottom. In some cases, these map on to current trends fairly well, in other cases, they do not.
Because of the bias that arises from extended phenotypes and the interaction between the genes and the environment, it is difficult to rank races in terms of their genetic predisposition to fertility as of right now. In the future, I predict race differences fertility to be largely a function of four variables: extraversion, mental stability (not necessarily low neuroticism, more like inverse p-factor), and attractiveness. Conscientiousness and intelligence might go from negative predictors to neutral or even positive predictors of fertility as childbearing becomes more reflective of intentional rather than impulsive behaviour.
Without going through the unpleasant effort of ranking races in terms of extraversion, mental stability, and attractiveness, I would rank the genetic predisposition of races to having children in the childbearing environment of the near future to be:
French
Hajnal Europeans (English, Dutch, Germans, etc)
Oceanic people, Central Asians, and Indonesians (not sure where to rank these)
Slavs, Southern Europeans, Ashk Jews, Mestizos, Mulattos, MENAs and Finns/Estonians
Sub-Saharan Africans and Subcontinentals (Asian Indians, Bengalis, Pakistanis)
Most mixed-race people
South Eastern Asians
North Eastern Asians
I ranked Hajnal’s genetic fertility above what would be expected from the three main phenotypes due to the fact that the current international mating environment most resembles that of Hajnal Europe, which likely enables their (unusually high) ferility. The French benefit from the hajnal phenotype as well as the breeder selection effect, where populations that go through demographic transitions earlier should, over time, become more genetically predisposed to having children. East Asians and Subcontinentals operated in an environment where most marriages were arranged, as such their personalities are not as well-adapted to a competitive and open mating market. Sub-Saharan Africans, despite being extraverted, do not seem to be that interested in intentionally having children; for this reason I predict them to have unexpectedly low levels of fertility in the future. Mixed race people will have unusually low levels of fertility due to two reasons: people generally have a same-race preference for mates, and that interracial daters are probably selected for phenotypes that are negatively causal for fertility.
Perhaps the reason Turks are so fertile is because their testicles had to become more robust and potent to handle a life of being jostled on horseback. Herodotus says that the Scythians sometimes suffered infertility because they wore pants too often and were always riding around on horseback.
Ashkenazi Jews had explosive birth rates for much of their history and still in religious circles retain high birth rates, so I'm a little surprised you rank them lower than Central Asians.