Penis envy?

In a Vertebrae Palaeontology lecture...

David Norman: At this stage it becomes normal to be obsessed with reproduction - willies and such

[Student gets up to leave for some water]

David Norman: Sorry, did I offend you?

[Class laughs. Student goes red]

...

[Later]

David Norman: Willies don't get preserved in the fossil record, at least as far as I know