I think it’s really adults who are uncomfortable with this whereas at a young age children are not uncomfortable at all and don’t freak out about these things. I was intensely curious about what a penis looked like as a child and the line drawings in the book my Mom gave me didn’t really clarify it. I used to dream that someone was going to finally reveal what a penis looked like and I’d be excited (not sexually, more about curiosity) in the dream, but since my own mind was creating the dream and it didn’t know, the dream’s ‘revelation’ was always incorrect and disappointing. My mind would create penises that looked like the seaweed pods we had seen on the beach at our last vacation, and I’d think, “Oh is that all it is?”
The biggest deficit, though, in my early anatomy lessons had to do with testicles. I was barely aware of them as a thing and had no idea what they were, even exactly where they were. I remember asking my Mom what that other thing was that boys had and she was mystified (maybe because I perceived and referred to the scrotum as a singular item and of course did not know the name for it or that it had two items inside it.) They became this huge blank in my head. A doll would have helped is all I’m saying.