Mutants (also known as Homo Superiors) are people who posses the X-Gene and developed superhuman powers and abilities that most could not control properly or at all or even change their appearance. This gene manifests at puberty during a teen's life, often at times of great emotional stress. According to Pyro, it's been discovered that males (human or mutant) carry the mutant gene and pass it on.
- Sebastian Shaw: "We are the children of the atom; radiation gave birth to us. What will kill the humans will only make us stronger."
- Jean Grey: "Ladies and Gentlemen, we are now seeing the beginnings of another stage of human evolution. These mutations manifest at puberty and are often triggered by periods of emotional stress."
- Jean Grey and Professor X: "Mutation: it is the key to our evolution. It is how we have evolved from a single-celled organism into the dominant species on the planet. This process is slow, normally taking thousands and thousands of years. But every few hundred millennia, evolution leaps forward."
- Mystique: "Mutant and Proud"
- Magneto: "Tomorrow, mankind will know that mutants exist. They will fear us, and that fear will turn to hatred."
- Storm: "Neanderthals, we once believed that they were wiped out by years of conflict with a much more advanced branch of humanity called Cro-Magnon, but recent research in to our own DNA suggests that these two species may have inter-bred, evolving into modern humans (asks class) into what? (Class: Us) Us."