This is an aboration of our times . .
. . due to the current extreme cost and legal reprecussions of offspring to the well-to-do. Historically (and prehistorically) the powerful have had more offspring, and their offspring have had a far better chance of survival - thus the evolutionary factors.
Our current society has bent and violated the natural order and natural limitations to the extent factors such as sex and power have, of necessity, been turned to uses not intended by nature.
Poor and uneducated societies continue in the natural ways in a world where those ways no longer serve, and if they don't learn to deal with the new world order, they face massive die-offs, sooner or later.
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