When Squirrel Girl came onto the scene, in her very first story, she told Iron Man that she was a mutant, but didn't like people to know.
And indeed, the Marvel website says she is a mutant, just in case there was any doubt.
But, like Quicksilver and Scarlet Witch, it looks as if that is to be taken away from her. In the first issue of her new post-Secret Wars series, it's made clear. She had medical tests and everything to prove it…
Could it be that Marvel have plans for her, that being a mutant – and thereby related to the X-books and Fox franchises – would be problematic?
UPDATE: It has been pointed out that this is a handy way for Squirrel Girl not to be affected by the mutant-killing/sterlising Inhuman terrigen mists and have to go off planet, or whatever.
Comics courtesy of Orbital Comics, London. Currently hosting the Observer/Comica Graphic Story Story Exhibition.