The number of children per woman depends, as has been said, on biological and social factors which determine: (1) the frequency of births during a woman's fecund period, and (2) the portion of the fecund period--between puberty and menopause--effectively utilized for reproduction.
This idea of Aristotle's has proved marvellously fecund; and in truth it is the only idea covering quite the whole area of cenoscopy that has shown any marked uberosity.