[Opinions] actually...
in reply to a message by Isla
Actually, it can happen to identical twins. I've read several articles in magazines and newspapers about a set of twins like that (it's always the same set, and I've never heard of another set of MZ twins like this), where they're identical, only one is white, with gingery coloured hair, and one is the kind of skin tone you would expect from a child with one white parent and one black one (as these girls had). Apparently it occured as a result of the paler twin not getting the melanin she should have received from her dad's genes.