An important point I didn’t hear - admittedly I didn’t have time for the full lecture. Number of babies does not equal number of adults in the next generation. Looking at averages obscures the huge importance of infant mortality.
Europeans in the 17th century had scads of children because so many of them perished before puberty. If you factor them out, the average number of adult children is a whole lot smaller. Likewise, infant mortality skews the numbers on average lifespan. Now that whooping cough doesn’t carry off all our brothers and sisters, we no longer feel the need to knock up each wife ten times. This might also be a plus for women.
