In many stories with "magic", the magic potential of a person is passed down through bloodlines. So one could stretch this concept into a thinly veiled cover for racist beliefs that some bloodlines/races (Wizards, Jedi, Aryans, etc) are better than others. The better system IMO is where "magic" is something that a person picks up through hard work and training rather something that they're born with. But then this turns into a debate about whether IQ is nature vs nurture.
