An Explanation for Declining Fertility - Vox Popoli

 The collapse of the Selective Turnover Coefficient (d) from the ancient hominin baseline of 0.86 down to a modern level of 0.015 represents the functional shutdown of natural selection’s primary mechanism for the human race. For hundreds of thousands of years, high mortality rates before reproductive age served as an unyielding purifying filter, culling highly deleterious mutations and maintaining the structural integrity of our species’ code. By effectively reducing this mortality barrier by over 99% through modern sanitation, medicine, and infrastructure, humanity has unplugged its biological safety valve. Without this selective cleansing, the human genome is now entirely defenseless against a relentless, generation-by-generation influx of genetic errors, transforming our collective gene pool into a one-way accumulation sink for deleterious mutations.......

https://voxday.net/2026/05/19/an-explanation-for-declining-fertility/ 

.....This says nothing about the various environmental and lifestyle factors, such as highly-processed diets to endocrine disruptors like microplastics, that tend to dominate contemporary public health discussions. Within this framework, these external stressors do not compete with the genetic calculation; they represent an entirely separate, compounding layer of physiological risk. Nor should this be confused with overpopulation, mouse utopia, feminism, or female education, all of which affect the rate at which women choose to have children, not their raw ability to do so.

This 15-to-19 percent calculated degradation is a structural floor calculated solely on the mathematical basis of the collapse of d, meaning any negative impacts from modern chemistry or lifestyle only serve to further aggravate a species reproductive engine that is already operating less efficiently than before due to an unselected genetic load.

If you want to learn more about this, the science is developed in THE FROZEN GENE.