article_snippet: The odds of a mixed race couple having twins of different colours are a million to one.
article_snippet: Skin colour is believed to be determined by up to seven different genes working together.
article_snippet: If a parent is of mixed race, a parent is of mixed race eggs or sperm will contain a mixture of genetic codes for both black and white skin.
article_snippet: However, if both the egg and sperm contain all white genes, the baby will be white.
article_snippet: And if both contain just the versions necessary for black skin, the baby will be black.