Kid Flash always had the coolest origin in comics, at least from my POV.

Of all the kid sidekicks whose origins happened to the 'adult version' first...Kid Flash had the coolest origin comics!

This whole discussion confirms to me why I have never enjoyed "side-kick" superheroes.  I have never enjoyed the DC or Marvel incarnations.  I never liked Bucky, but I do like the Winter Soldier !  And I could never figure out why a "creature" like Batman would have a kid named "Robin" to be his partner in crime !  It's like "Space Shuttle Man" having a sidekick named "Teddy Bear."  If anything, Robin should have been named after some other creature in the bat family of species.  But Robin?  C'mon !  Robins are brown and wake people up in the morning with beautiful songs.  They don't fight crime!  It just doesn't work !

These feelings were true when I was a kid.  They are still true now that I am an adult.  When I was a kid, I wanted to be like the adults in the Fantastic Four.  When I became an adult, I appreciated (at a deeper level) the adult lives of the Fantastic Four and of course the Spider-Marriage!  Note: I live in reality now and no longer want to be Reed Richards !  At this age, comics are an escape for me in which the main characters or teams are populated by adults.

But . . . . (and this is a very important "but") I sincerely enjoy Marvel's (Heinberg & Cheung's) Young Avengers !  Why?  Because they are their own group. In many ways they have only superficial similarities to their supposed adult counterparts.  As an example, Hulkling is not a teen-age version of the Hulk.  Yes, the YA are kids, but they aren't trying to be like the Avengers.  They are making a sincere attempt to be themselves and make a difference in their battle against super-villains.  This is refreshing and I sincerely believe that Heinberg has accomplished something unique that no other comic book has done, even the Teen Titans!  And the kids in Avengers Initiative are also done well for reasons similar to YA !

By contrast, consider the Ultimate Fantastic Four.  I understand why this comic exists and what it hopes to achieve.  But for me personally, it has been the biggest disappointment I have ever experienced with Marvel ! I love the adult versions of Reed, Sue, Ben and Johnny !  But the younger, teenage versions in UFF, well, I tried the first 25 issues to be open minded, but just couldn't stay with it.  I remember reading the last page of one of my last issues and Sue was exclaiming "Mom" !  (or was it? "Dad"!)  And I thought, "I'm done!"

I hope that others have and will enjoy comics with teen age side-kicks.  Meanwhile, I will stay true to my friends who are adults, (with Y.A. & A. I. as notable exceptions ) !

PS: JB's Kristoff was the best ever "child" character to be mentored by someone in the MU, particularly Victor Von Doom !  I personally feel that JB's work on Doom/Kristoff supercedes anything done by anyone else on the Reed/Sue/Franklin/Valeria family.

I always figured Kirby and Simon's "kid gangs" were based on the popularity of the Dead End Kids and Doc Savage's sidekicks.

As for Robin and the rest.  I've always liked the Teen Titans, but prefer the sidekicks as occasional guest stars in their mentors books rather than regulars