The gender gap in career attainment is partially accounted for by women underestimation of their own achievement, and although that today has changed considerably, women still have a tendency to exclude themselves from certain careers or situations, out of fear or distrust, and more so if they come from Latin, Asian or Middle Eastern countries.
I believe the answer is: <span>education levels among women increase.
Studies show that as educations levels among women increase, the awareness of the hardship that they might encountered when they're having too many children (or too early) started to increase. This could lead to small number of newborns and lead to zero population growth.</span>
<span>The Roman empire was physically united by good roads and bridges and secure sea lanes.</span>
It’s a Babylonian code of law in the ancient Mesopotamia :-)
