What's funny was the 21 yo I was with was telling me how many of her friends / fellow students were sleeping with the professors at her university - these guys were well into their 50s.
This type of thing used to be common, maybe it still is from what you say. At some point people started to frown on it. Something about the power dynamic, the professor was a person a young girl would look up to, therefore it became smarmy for the guy to take advantage of that. It might even be illegal now for a professor to sleep with his student, I'm not sure.
Yeah, sleeping with 20 year olds is a known perk of being a professor, lol
I mean, that's what the movie The Nutty Professor was based on.