“Any preliterate human societies that included individuals old enough to remember the last great catastrophe had a much better chance of surviving the next one than did societies without such old people. The old men were not at risk from childbirth or from exhausting responsibilities of lactation and child care, so they did not evolve protection by menopause. But old women who did not undergo menopause tended to be eliminated from the human gene pool because they remained exposed to the risk of childbirth and the burden of child care.