In the Marvel Universe, mutants are humans who are born with a genetic trait called the X-gene which grants them natural superhuman abilities. Due to their differences from the majority of humanity, mutants are subject to prejudice and discrimination and many X-Men stories feature social commentary on bigotry and justice. The X-Men have fought against a variety of enemies, including villainous mutants, human bigots, supervillains, mystical threats, extraterrestrials, and malevolent artificial intelligences. In most iterations of the team, they are led by their founder Charles "Professor X" Xavier, a powerful telepath who runs a school for mutant children out of his mansion in Westchester, New York, which secretly is also the headquarters of the X-Men. Their stories have frequently involved Magneto, a powerful mutant with control over magnetic fields, who is depicted as an old friend of and foil to Xavier, variously acting as an adversary or as an ally.