Only thing I distinctly remember is one girl speculating that erections are caused by a bone and the whole class laughing at her (yes, we still remember that embarrassing thing you said 25 years ago). I wish I had known back then that some mammals actually do have a penis bone. I felt kind of sorry for her.

Oh, and I remember that we learned that intersex people existed. At least the purely biological side. And that was at a catholic school.