Mutants. Some people are just born with powers--Emily has her magnetism, Scott has his eye beams, Jean has telepathy AND telekinesis, that Frost woman Dad argues with when she visits has telepathy and the diamond shapeshifting thing, Warren has his wings, Aunt Raven has her blue skin and more general shapeshifting...
And it's not only wings and blue skin that can be different, physiologically. That's how Emily has two dads.