When I was in highschool, we had one boy in our social group - amongst a lot of girls. I always think of how horrible it would have been for him - to only have female friends but to always be treated like some sort of sexual predator by a lot of our parents. Some seemed to treat him as if the only reason he hung out with us was to get in our knickers... when really, the true reason has been revealed now - he was an effeminate gay, and simply got along better with girls.
Out of a group of about 10+ girls, only 2 of us were allowed to spend nights with him. I think it's why we became the closest to him - because our parents didn't treat him like a pervert.
I slept over his house plenty of times. Yes, I saw his penis eventually, but it wasn't sexual... it just happened. I also ended up seeing the various body parts of my female friends too. It wasn't about trying to shag each other though.
He was the only boy invited to my baby shower, and some people treated it as if it was odd to have a male there... but he was my friends, and I wasn't about to reject him for various events just because he happened to have a penis.
Would I let DD sleep over at a boyfriends house? No. But would I let her sleep over a boy who was her close friend's house? Of course!
It's not too hard to tell the difference...