For better or worse, this is more historically common with men, even in previous generations. Both of my parents' fathers were in their late 40s when they were

For better or worse, this is more historically common with men, even in previous generations. Both of my parents' fathers were in their late 40s when they were born, in the 1940s. And yes, that left the fathers quite old when their kids grew up, and very old by the time they were or could have been grandfathers. My paternal grandfather died before I was born, and I only knew my maternal grandfather because he lived to a quite old age (he was in his 70s when I was a young kid, and lived into his 90s). There are elevated risks of some diseases with older men, but fertility declines slowly, so it hasn't needed space-age technology for that kind of generational structure to emerge.