A partial explanation.
TLDR: without natural selection or eugenics we're fucked
>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.
>The immediate danger of this relaxed selection regime manifests as a rapid, compounding increase in genetic load, targeting our most complex physiological systems. Because intricate biological functions like human fertility, neurodevelopment, and metabolic health are polygenic—relying on the flawless coordination of thousands of interacting genes—they possess a massive mutational target size. Every generation we advance past the 1900 demographic turning point injects new, un-cleansed, mildly deleterious mutations into these precise pathways. As a result, the widespread declines in baseline reproductive viability observed in the 21st century are not merely temporary products of environmental toxins or socioeconomic shifts; they are the predictable, mathematical consequence of a degrading genetic operating system that is losing its structural integrity.
>Based on the unyielding arithmetic of mutation accumulation in a fluid genome, the 130-year span between 1900 and 2030 encompasses exactly 5.2 generations of uncleansed genetic replication.
>Multiplying these parameters dictates a compounding biological degradation rate of roughly 3 to 4 percent per generation. When compounded exponentially over 5 generations without the purifying filter of pre-reproductive mortality, the strict mathematical expectation is a 15% to 19% reduction in core biological fertility by the year 2030 compared to the 1900 baseline, a reduction that is driven by the unchecked accumulation of the species’ polygenic mutational load alone.
>This says nothing about the various environmental and lifestyle factors, such as highly-processed diets to endocrine disruptors
>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.
https://voxday.net/2026/05/19/an-explanation-for-declining-fertility/
TLDR: without natural selection or eugenics we're fucked
>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.
>The immediate danger of this relaxed selection regime manifests as a rapid, compounding increase in genetic load, targeting our most complex physiological systems. Because intricate biological functions like human fertility, neurodevelopment, and metabolic health are polygenic—relying on the flawless coordination of thousands of interacting genes—they possess a massive mutational target size. Every generation we advance past the 1900 demographic turning point injects new, un-cleansed, mildly deleterious mutations into these precise pathways. As a result, the widespread declines in baseline reproductive viability observed in the 21st century are not merely temporary products of environmental toxins or socioeconomic shifts; they are the predictable, mathematical consequence of a degrading genetic operating system that is losing its structural integrity.
>Based on the unyielding arithmetic of mutation accumulation in a fluid genome, the 130-year span between 1900 and 2030 encompasses exactly 5.2 generations of uncleansed genetic replication.
>Multiplying these parameters dictates a compounding biological degradation rate of roughly 3 to 4 percent per generation. When compounded exponentially over 5 generations without the purifying filter of pre-reproductive mortality, the strict mathematical expectation is a 15% to 19% reduction in core biological fertility by the year 2030 compared to the 1900 baseline, a reduction that is driven by the unchecked accumulation of the species’ polygenic mutational load alone.
>This says nothing about the various environmental and lifestyle factors, such as highly-processed diets to endocrine disruptors
>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.
https://voxday.net/2026/05/19/an-explanation-for-declining-fertility/
