A woman gets one x chromosome from her father and one from her mother. "Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in cells other than egg cells. This phenomenon is called X-inactivation or lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells." When a woman conceives, is the x chromosome she passes to the child a complete copy of one or the other of the x chromosomes she inherited from her parents, or is it a mix and match version of her two x chromosomes? It might seem late in the game for me to be asking this question, but I have always found it confusing. Marleen Van Horne