17 karma · joined July 5, 2019
Perhaps I over stated the case by saying inevitable. It's quite feasible that the consequences of highly fertile people overbreeding will be a reduction in civilizational complexity, which will lowerthe total population.
https://www.amazon.com/s?k=Who+We+Are+and+How+We+Got+Here&re...
“First Law: All human behavioural traits are heritable.
Second Law: The effect of being raised in the same family is smaller than the effect of the genes.
Third Law: A substantial portion of the variation in complex human behavioural traits is not accounted for by the effects of genes or families.”
Beyond that though, the genetics of human fertility is pretty well understood. Here's a (now fairly old: from 2016) GWAS study on human reproductive behaviour: https://www.ncbi.nlm.nih.gov/pubmed/27798627
They show genetic correlations between reproductive traits and other behavioural traits in Figure 3. You might find it helps you develop an intuitive understanding. Happy to answer questions if you have any.
Then this study more directly measured fertility's rate of evolution: https://www.pnas.org/content/115/1/151. They used UK Biobank data (genetic data from 157,807 female and 115,902 male unrelated samples). They found the 'Age at First Birth' is the most strongly selected trait in the British population. So in the future we can look forward to a world filled with teenage mums.
That this is not obvious to everyone is just a testiment to how little people understand about evolution.