We’re probably just using the “overengineering” that the evolution put into us to account for much harsher living conditions that existed previously. I have no other explanation, in any case. That’s also why a lot of us are fat.
There used to be more age difference between husbands and wives. Men who outsmarted and out gunned the competition to live longer got to reproduce a lot more… evolution does select for men who reproduce more later.
What is the other factor pushing it up?