From a functioning reproductive point of view, modern women are special not just because they tend to have children later than their predecessors; it’s also only in rather recent times in our history and prehistory that women have spent more than a few months of their reproductive life ovulating and menstruating.

Over the last say 100 000 years, women have typically spent their reproductive years either pregnant or breast-feeding their infants.

The nine months of each pregnancy and the two or more years of (unsupplemented) breast-feeding that followed each pregnancy stopped the ovaries from ovulating.

If each weaning was soon followed by another pregnancy, then the normal human female condition, biologically was -- and arguably still is -- to ovulate and to menstruate not more than 10 or 20 times in a lifetime.

There’s more about this on WebPage 2.