Originally Posted by
Sutekh
As I understood it, back in the day, thanks to Celestial tampering, humanity had the potential for mutation. A small percentage would be born with that potential unlocked, and become mutants around puberty (or sooner, in some cases). Most would remain 'latent' through life, but could get triggered by something, like cosmic rays, gamma rays, a radioactive spider-bite, a super-soldier serum, Terrigenesis, etc.
According to Days of Future Past's future scenario, there was also a percentage of humanity that had *no* potential for mutation, latent or otherwise, and, presumably, if exposed to a massive dose of gamma radiation, etc. would just die horribly crapping out their intestines.
So, based on that, anyone who isn't a straight-up mutant, and isn't getting their powers from tech, or being related to a god, or magic, or some alien or extra-dimensional stuff, people ranging from Spider-Man to the Hulk to the Fantastic Four to Captain America to the entire Inhuman race, are 'mutates' or 'latents.' (With the Inhumans, it was Kree technology that awakened their latent mutation, but the Terrigen didn't give them the ability to mutate, or else it would have worked on the Kree themselves, and they never would have needed to use it on humans.)
Presumably anyone who has internalized the size-changing ability granted by Pym particles (such as Hank, Cassie and Janet, at least), also counts. (And perhaps Scott is *not* a latent, explaining why he has never gotten with the program, and still needs a fresh dose of particles whenever he wants to shrink or grow?)
That all said, I'm fairly certain anyone currently at Marvel has forgotten Days of Future Past, or that the Celestials gave humanity the X-gene, or what the word 'mutate' means. Several stories have had whole towns turned into Hulks or Spider-Peeps, which, according to their own theory, would have flat-out murdered whatever percent of said towns were *not* latents, and would have just suffered the usual effect of massive radiation exposure instead of 'Hulking out.'
Marvel itself likely doesn't remember this stuff, and it's pretty clear that they either don't have, or don't bother to read, any sort of story bible, like the old Marvel Handbook days, when everything was sort of codified in one central place, and, however imperfect they were at it, the editors at least *tried* for some semblance of internal consistency across the titles.