I decided to grant Sculplin his request for boys and their boys. It's not as much fun because the short of it is: Naked guys are gross.
You can touch a boob and it's not a far stretch from an affectionate "arm around the shoulder." If you touch a guys uglies a good hand washing is in order. People talk about guys being sexually stimulated by vision and girls another way --- maybe some day we'll figure it out and we all pray it isn't a big wad of money ("security," they like to call it). Without seeing the research, I am willing to agree that they are on the right track. It's hard for a girl to go wrong with cleavage. A guy with socks in his trousers is likely to get attention, but is it good attention, Tom Jones?
Probably not. I'm guessing a 9/1 opinion ratio of "creepy" to "all that." Better to be like the South Park guys and jest with the issue. Most girls seem to prefer a sense of humor to an actual scary bulge.
I'm no expert, though. The ancient Greeks seemed to prefer the male form to the female. Michelangelo's "David" is a piece from the Renaissance in Italy (c. 1500) but a lot of the Roman stuff was copied or heavily influenced by the Greeks. There are several depictions of "David" from several different artists, many of which show David standing over Goliath's severed head. I think this version is supposed to exude the psychological tension before the fight. There is more emphasis on David's juevos than muscle bulk and even less on the sling with which he will slay the giant. Yes, naked dudes have been glorified through art for thousands of years.
When the Greeks occassionally immortallized a woman, it was usually more of a full figure than it was skin and bones, as we all seem to prefer these days. If you go tens of thousands of years into history you will find statues similar to "Venus of Willendorf" all around the world. Who's that girl with the junk in her trunk?
Testicles are more gross than interesting. Best to keep them tucked away. Inventing a pair of "wonder-briefs" would be a horrible idea.