My parents were the same way. My mother only said that I couldn't read one book series, and that was based on what my aunt told her. That was The Sleeping Beauty trilogy by Anne Rice, which were like the mid 90s 50 Shades I think, just better written.

My mom got the warning because I was really into Anne Rice's Vampire books, so I would be trying to read anything else by her that I could get my preteen/teenage hands on. They just told me it was erotica in more vague terms. I was cool with it, I had tons of other stuff to read anyway. :D