Toralf said, among other things:
On a related note, another common misconception is that nobody did live to the age of 65 a few hundred years ago, because the life expectancy at birth was 40 or whatever. The truth is that the main contribution to the lower life expectancy was a very high child mortality rate - the chance of getting old *if you survived childhood* wasn't necessarily that much lower than today.
Two big hurdles, I think -- childhood yes, and child*birth* ...
