conditioned to breed at or around the replacement level The concept to read up on here is r/K selection. Life is certainly judged by how many offspring, but th

conditioned to breed at or around the replacement level The concept to read up on here is r/K selection. Life is certainly judged by how many offspring, but there are various strategies for producing them, and one of the trade-offs is number vs. investment in each. Among all animals humans are far at the r-strategy end (high parental investment). But different societies choose slightly different points, probably related to their history of farming. And the richer countries today are those traditionally towards the r-strategy end.