Anonymous wrote:This is probably a normal age difference prior to about 1970. Men were expected to be over their "wild oats," well established and able to earn a living, women needed to still be of childbearing age.
I don’t know about 1970, especially in the USA, but large age gaps have been the norm at different times and places throughout history.
I think age gaps correlate with income inequality. In higher inequality times, people value economic security, which favors older, more established men. In the mid 20th century USA, income inequality was low, so I’d guess that age gaps were smaller as there was less concern about a man’s ability to provide. Inequality has been growing since around 1970, actually