Skin (2008)
Skin is a British-South African 2008 biographical film – based on the book When She Was White: The True Story of a Family Divided by Race by Judith Stone – directed by Anthony Fabian, about Sandra Laing, a South African woman born to white parents, who was classified as "Coloured" during the apartheid era, due to a genetic case of atavism. Skin premiered at the Toronto International Film Festival on 7 September 2009.
More at Wikipedia.