I agree with Laura's (Uabasson) post.

But, I also think it is related to the perception of beauty. I could never understand WHY a male body is not considered beautiful? I think the roots of this lay in the education. I personally think that a male body can be as beautiful as a female body, and viceversa. People don't look at the human body with their eyes, they look with their mind (which is full of prejudices). You just have to look for it. A man's behind can be as sexy as a woman's. I know so many straight girls that don't see half of the beauty I see in men.