I know that vitiligo is passed down in the females on my mum's side of the family, and I've never seen it to a full-body extent as Michael Jackson claims. However a good point of reference is his sister, LaToya Jackson. She also appeared darker in skin tone when she was younger, and gradually became lighter as she got older. Indeed at one point she and Michael looks scarily like each other;



So unless both had exactly the same treatments then there could be something in Michael's claims that it's his biology, i.e. nature not nuture, that is to be attributed to his changing appearance. Saying that it has been confirmed that not only did Michael undergo more surgery than he claims (most of it, if you're to believe tabloids, in relation to an incident whereby he suffered burns to his face filming a Pepsi commercial), but that the Jackson family themselves used to use skin lightening creams. Considering how radical the changes are in Michael's appearance, it's safe to assume that outside influences were involved, and for whatever reason Michael found it neccessary to change his apperance from that of a black man to a white man. Whether or not his vitiligo go to a point whereby it was easier to "go one way rather than the other" is up for debate. Some even claim that Michael did such surgery to make himself more marketable to the white population, thusly making it the hugest publicity stunt ever (though it backfired badly, with his freakish appearance and "personal transgretions" contributing to his downfall in the mid-90's).