I come from a modest family, and my (by this time grown) brother once completely flipped out because he saw my mother in… gasp!… her slip (she actually had her skirt on, too, but was ironing her blouse)!!!
Weird.
Luckily, I spent a lot of time with my grandparents, who were pretty free-wheelin’. In fact, my parents once took me with them to watch some “stag films” at a friend’s house when I was about a year old (they couldn’t find a babysitter, and hell, I was a BABY–I’d never know what was going on)…
Apparently I mistook the woman in the porn flick for my GRANDMOTHER, and started pointing and calling, “Nana! See NANA!”
We left shortly thereafter, and my mother had a “talk” with my grandmother.
As a result of my “dual existence” childhood, I am:
a) the only one in my immediate family who doesn’t attempt to hide my goodies around the others (especially now that my dad and brother are dead and it’s just us hens)–they think I’m a complete exhibitionist, and are slightly appalled.
b) secretly of the belief that the person who wields the power in the household is the person who can walk around naked in front of anybody in that household (like, say, the mom in a house containing her husband and three daughters, or my best friend in a household containing her husband and ME)–I am determined to be this person when I grow up (actually, I guess I AM this person, but the dogs are always naked…). 
I can remember reading a Gary Snyder poem for an undergrad class… I think it’s called The Bath… describing bathing with his wife and toddler son. I thought it was beautiful. Other people in the class found it disturbing and inappropriate.
Diff’rent strokes, I guess…
But I agree with you–I think people can get too hung up sometimes on the nekkid booty. JMO…