It has been known for decades, that the fertility in humans is rapidly declining, and that this started after WW2 [1,2]. The causes of these are mainly related to endocrine disruptors, however, the statistical basis for this is still too poor to conclude that this is the main cause. This is so, based on that there are no samples of blood with endocrine disruptors taken from the early 50s, that sufficiently build this hypothesis.
However, a novel hypothesis proposed here, is that the lack of fit men, who mostly died in WW2, may be the cause. It is known from Darwins evolutionary theory that a pool of a high number of fit males in an ecosystem, and of fit females will preserve the fertility constant and keep the change of fertility, dF/dt at zero (no reduction in number of offsprings).
However, since 50 million men and women died in WW2, mostly men aged 18-30, we can remove a great part of the fit males from the ecosystem of humans after WW2. This would affect the fertility change, and give a dF/dt
The decline in fertility rates in many parts of the world is a complex phenomenon that is influenced by many factors. While the loss of life due to World War II and other conflicts may have had an impact on the population, it is unlikely to be the primary cause of declining fertility rates.
There are several factors that contribute to declining fertility rates, including:
It is also important to note that declining fertility rates are not a universal trend and that different regions and countries are experiencing different patterns of change. In some parts of the world, fertility rates remain relatively high, while in others, they have declined to below replacement levels.
In conclusion, while the loss of life due to World War II and other conflicts may have had some impact on declining fertility rates, it is unlikely to be the primary cause. Instead, it is the result of a complex interplay of social, economic, and environmental factors.
Your hypothesis doesn't seem to apply to countries that did not participate in the war but w hich fertility rates declined prior, during or after that war like some in Latin America
Attached the map of lowest vs highest fertility. From https://en.wikipedia.org/wiki/Total_fertility_rate
I don't see any comment to the map. Sincce the timing of the events is crucial to your idea, and I gather this is a map of the current situation, it doesn't help the discussion.
There is a very-very large number of works on fertility decline and its causes in the demographic literature
Another cause of infertility growing up is light during sleeping as for women and men because it affects the secretion of melatonin with effects on the pituitary function. This “light” can be a fluorescent alarm-clock, illumination in the street breaking into the bedroom by the window and so on… For men another cause is warmth near the testicles.
Just a few classics, then you can write "fertility decline" in google scholar and you will find many-many more.
Coale, Ansley, 1967, Factors associated with the development of low fertility: an historical summary. United Nations, Proceedings of the World Population Conference.
Cutright et al, 1976. Structural determinants of fertility in Latin America: 1800-1970. American Sociological Review, 41.
Höhn and Maskensen, 1982. Determinants of fertility trends: theories re-examined. Liege, Ordina
Then you have several publications from a large Princeton Study on fertiity decline in Europe (Lesthaeghe on Belgium, Livi-Bacci on Sapin and on Italy, Knodel on Germany,etc.
And, actually, after WW2 there was a "baby boom" (increase in natality) in the USA and, to a lesser degree, other countries that partcipated in the war.
The decline in fertility rates around the world is the result of various social, economic, and cultural changes, including increased access to education, contraception, and economic opportunities for women, as well as changes in family structure and values.
While it is true that World War II resulted in the deaths of many men of childbearing age, this factor alone cannot account for the decline in fertility rates. The impact of the war on fertility rates varied widely across different countries and regions, with some countries experiencing a baby boom in the years following the war, while others experienced a decline in fertility rates.
Furthermore, the impact of the war on fertility rates would have been temporary, as the population would have replenished itself over time. Additionally, other factors, such as improvements in healthcare, increased urbanization, and changes in cultural attitudes towards family size and childbearing, have contributed to the long-term decline in fertility rates.
In summary, while World War II did have a significant impact on the world, it is unlikely that it can be solely responsible for the decline in fertility rates observed in recent decades.
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