Unless they retcon in a wolverine style "slow aging healing factor" or some kind of suspended animation. Magneto's origin of being a child in the holocaust is getting a little hard to believe.
 
Forgive me if this has already been done in one of the books, I haven't kept up with X-men comics in a while and just read a few recently.

I was wondering the same thing.  With someone like Punisher you just change the war. He originally was in Vietnam, now it's Iraq; but for Magneto it seems to be such an integral part of his story.  Maybe they could say there is a mutant who is capable of rejuvenating people, like a living fountain of youth.  In a way, alot of Marvel characters have this problem. DC fixes it by causing a Crisis every few years that reboots the universe. Truthfully I hope they keep aging the characters because I want to see how they mature and who takes their place. I'd be real cool if they create one Earth 616 based universe which they progress in real time and another universe which adheres to the current slowed time model.   

Magneto's body is not as old as his mind. He was reduced to an infant by Alpha The Ultimate Mutant, and was then restored to his prime by Erik the Red. So it's still feasible that he was a child during the Holocaust.

It is exactly as Korg says it. Still it is implied that Charles Xavier is the same age as Magneto. I can't think of a similar thing that happened to Professor X. Maybe after his body was occupied by the Brood?

Xavier's gotten a new body a couple of times. Ironic how he always gets crippled anyway.

This is going to become more of a problem as time goes on for every character, just depends on how it's handled by the writers but the easyest thing to do is reveret to clone bodys ect.

I'd just like to assume that mutants have a longer life expectancy, maybe 200 years or so (unless killed in battle) 
Mystique and Wolverine are each well over 100 (although that's due to regeneration) and Destiny was close to 100 when she was killed. Several mutants are immortal by nature, possibly Cannonball and what's left of the Externals, why not just say their mutant metabolism keeps them at their peak for a longer period?

To be honest, I liked the Magnus Civil War Origins, Magnus was a far cooler Magneto, don't know why though.

why is this focused on just magneto and xavier? what about spider-man? in actual years, he would be over 50 by now! he started when he was 15 is what it says in civil war. 
 
or any character for that reason. idk, i think its just part of the fun and something in comics you just gotta shrug your shoulders too and move on

" @zombietag: The Holocaust is a very specific time frame. Spider-Man could have become Spider-Man at any given time. There is not the specific window of time in which he grew up as there is with Magneto. "

 This has bugged me more and more over the years as well. MC2 could have been a way of fixing this, but it turned into making every superhero talk like Jubilee during her Generation X days, which made me want to stab my eyes out. Given that mutants all seem to age normally from puberty onward, it's surprising to see Scott Summers and a lot of other ones seem to have topped out around their late 20's without having access to whatever it is Nick Fury takes to freeze his aging. Plenty of mutants could have excuses based on their physiologies that would explain why they would age more slowly, but the same can't be said of all of them (Cable, for instance, just got about 16 years older).

wont he always be a child back then?

A while 

i have faith the writers will find a logical way to make sense of this

Magneto's origin story is eventually going to be a huge problem. Sure, his youthful physique can be explained by the rejuvination thing - basic comic book logic - but the fact that his age is tied to a real historical event will still screw up the ages of other characters. It has a domino effect. If Charles Xavier is supposed to be roughly the same age as Magneto, his age must also be determined by WW2, yet he still looks middle-aged. Magneto supposedly fathered Quicksilver and Scarlet Witch shortly after the war, but they are still portrayed as thirtysomethings.

Sooner or later, they're either going to have to let some of the characters age significantly, or just completely retcon Magneto's origins and maybe make him a descendant of a Holocaust survivor instead of somebody who actually survived Auschwitz himself. He may go on prancing around looking barely middle-aged because of the alterations in his physical appearance, but they really can't keep characters like Quicksilver and Charles Xavier frozen in time like average comic book characters since their ages can be determined by Magneto's true age. They can't all become rejuvinated by mystical alien technology.

(Logic be damned, I'll be terribly sad if the Holocaust story is retconned. I think Magneto has one of the most powerful and intriguing origin stories known to superhero comics.)

Didn't he already get de-aged?

I mean eventually the dude's gonna have to die, but unless Marvel gets its own Lazuras Pit, I don't think they can keep it up for that long. But I suppose if Sinister and Apocalypse can find new bodies, Magneto can probably work something out.

I remember X-Men: Evolution had Magneto use the same thing Cap used to keep young. Maybe they can work in something similar.