Never saw anyone naked in our house. I am the youngest of four children, so like Steve, shared a room with my brother and was always last in the bathroom in the mornings. I don't recall ever seeing him naked and never my parents.

It was at school that you saw naked boys during the dreaded annual medical and  later at secondary school in the showers. 
It just didn't happen in everyday life back then. 

Similar to Steve,
In my home with my mum and dad plus younger brother by 5 years it was pretty typical with locking bathroom doors around age 11 and occasionally being let in if you needed the loo! On occasion nudity couldn't be avoided on family holidays sharing a apartment which I hated at the time..

my mum was/is a control freak so didn't really worry about embarrassing me or my brother if we where taking too long in the shower etc! 

However I did spend virtually every weekend at my cousins house who are 8 months older than me! Twins.. and one other who is 18 months older than them.. so 4 boys and one bathroom! Which didn't have a lock..

Up until we was 13 my Aunt Kay would have a routine where she'd call the next boy into the bathroom as the other was getting out! It was awkward at the time with puberty etc but good looking back 

I did not grew up in a naturist family. But my father and my two brothers could take showers together, and were not ashamed of seeing each other naked. When i was a child i remeber beeing naked in the bathromm with both my parents. This was in the 1960's. I can still remember the beautiful naked body of my mother. When I was about 7 or 8 years old my mother started to cover herself up i bit. She was never completeky naked in front me anymore. She kept the pantys on, or wear a towel covering her vulva. but shehad no problem beeing topless in front of me. She could also change when i was presnt , but turned the back to me, so I could see her butt naked, but not her vulva.

I did not start to cover up in front of her, and she often observed me completely naked as long as I stayed at home. I started to sudy in an other town when i was 19. She didn't avoid to see me naked even after I got pubic hair and a adult size of my penis. 

I hoped that my mother one day, would dare to be completely naked i front oft me. I never dared to talk to her about it, and she never did. I got some quck glimpses of her dark pubic hair, but i dreamed about her beeing completely naked in front of me,

My reflections today are that I never had to hide my nudity gave me a positive view on Naturism. And I started to go to nude beaches when i was about 25 years old.

Growing up I would take baths or showers with my dad until I was about five. That was the closest my family ever came to naturism. I never bathed with my mom. In fact, at about this same time, I remember walking in on her when she was taking a bath. She freaked out. When I look back on it, if my family didn't do things like closing doors when changing clothes or bathing I think the way I saw myself in regards to my body image may have been different. The way I viewed the relationship between sex and nudity would have been different. Because it was hidden, it made one curious in the wrong way. As they say curiosity killed the cat.
By the time I got to middle school, I waited til I got home to shower after gym class. I was totally ashamed of my body. It wasn't til I discovered naturism did I start to get over this.
I could go on and on about this. The point is: If families don't have a hangup about nudity in the house, it will go a long way in keeping their kids from looking for answers in the wrong places. You don't have to be a naturist (at least not in the purest sense). 
I don't know if this makes sense. I'm having a hard time trying not to ramble.

I'll agree with nomadnz.  From an early age I never felt "odd" in being nude.  Finding those nudist magazines on our property (written about in other posts) just reinforced my beliefs and I think that is why I pestered my parents to allow us to go skinny dipping.  While there was only that one time with my siblings and my father it was significant for me and the result was that I was allowed to skinny dip by myself.