Nakedness in the gender

Girls don;t mind being naked together while guys will definitely NOT want to be naked together.

Example situation; gym locker room.

I think it's also a personal thing.  I couldn't care less about being naked along with other men or women.  I also went through those odd years of puberty in Germany, where nudity is hardly anybody's concern.  Everybody is naked beneath their clothes, so what?  I've actually found that girls are more likely to disrobe in my presence once they know I don't particularly care about nudity.  I have a feeling for anybody, it's not about being naked, it's being oogled (not necessacarily in a sexual manner). 

Men and women both worry about how they "stack up" against others, so in many cases I would think it's about embarrasment in partcular, instead of simply being seen with the pants down.  As for cultures, though, which do play a role, many cultures have toned down sexuality, or compartmentalized it, to the point where the undenyable connection between nudity and sexuality is weak enough to stay out of peoples thoughts, or at least out of their behaviour. 

And finally, as far as men/women are concerned, I think the differences there are based wholy on homophobia.  Since women are expected to be more affectionate and so forth, nobody thinks twice about girls hugging each other.  If guys do the same thing, "are they gay?" comes up soon enough.  Despite this being the internet, you can probably figure out how that translates into being naked together.

So for anybody who thought, "too long, didn't read"...

You're naked beneath your clothes, too.  Don't worry about it.  You seen one naked body, you've pretty much seen them all, so again, don't worry about it.