Who started the insanely muscular/busty trend in depicting male & female superheroes?

Where did the huge breasted & super ripped look originate? Which artist started this trend?

Em…I think it’s just been an evolution. They were always good looking people, they’ve just become more so in the intervening years.

I don’t think they’re “more so,” I think that they’re grotesquely so.

That’s just in keeping with the majority of superhero characters, though – they’re grotesquely exaggerated archetypes of virtue and excellence, the extremal limit of what we’d wish to be, so for their looks to follow the same pattern isn’t really that surprising.
I’ve always seen them in the tradition of the Greek heroes and demi-gods, who were often depicted as rather ripped themselves, and who provided the same mirror image of human interaction that gives us a ‘tu quoque’ justification to be OK with our own shortcomings (though today, most people look more to the various celebrities for that purpose).

For male characters, I’d go with Jack Kirby. C.C. Beck and Basil Wolverton drew hulking characters, but usually for laughs. Mac Raboy and Lou Fine brought real craft to muscular characters a little later.

Female characters were pretty demure-looking until Matt Baker got into the game. Then Jack Cole, Will Eisner and Bill Ward all one-upped one another for sexy females. Frank Frazetta was active a little later.

Most of these artists began around 1940 and hit peak proficiency by war’s end. Cole and Ward gave up comics and drew for girlie magazines in the 50s.

That’s kind of an interesting comparison.

Greek gods and Superheroes of today’s day share many characteristics, with the slight exception that our superheroes seem to be perfect, in some comics at least, where Greek gods had likable flaws.

Well, a lot of (today’s) superheroes are likewise flawed: Iron Man’s an alcoholic, Spiderman is a nerd, Batman is… Batman, and Superman is just a dick.
I think, while a one-to-one comparison might not be apt, they do serve a similar purpose to the heroes of old, both earning the praise for our virtues and suffering the punishments for our sins (and the same is to some extend true for celebrities, or at least their public images); in a way, one might argue that the Christian god is the ultimate conclusion of this ‘mirroring’ tendency: defined as perfect in every way conceivable, and he literally died for our sins on the cross.

Wiki puts some blame at Rob Liefeld’s feet, stating:

If this is a plea for more chubby superheroes, can we lose the lycra outfits?

I remember that in the 70s, the Legion of Super Heroes underwent a sharp transition in tone and style, from the slightly juvenile format it had had in the 60s to a more mature look, including changing most of the Legionaires’ costumes to be decidely sexier, both male and female.

Neal Adams

While Kirby was a precursor, he did not draw the kind of highly defined muscles that is the current style. Adams did. He was a master of drawing anatomy, and nearly all comics out today show his influence – the “ripped” look that is a requirement.

There are also influences from the comic strip. Russ Maxon and Burne Hogarth were drawing a superhero-style Tarzan in the 1930s. Milt Caniff was doing similar things in Terry and the Pirates at the time.

But none really had an influence. By the 50s, comic books were done in a cartoony style, with little attempt at showing off muscles. Kirby changed that, but Adams set the style still used. Liefield, etc., are just second-rate copies of Adams.

The second image down on this page is one of the more frequently cited examples of Liefeld’s anatomical excesses (SFW).