In the human body, each cell contains 23 pairs of chromosomes, one of each pair inherited through the egg from the mother and the other from the sperm of the father. Of these chromosomes, those that determine sex are X and Y. Females have XX and males have XY. In addition to information concerning sex, the X chromosomes carry determinants for a number of other features of the body, including the levels of factor Vlll and lX. If the genetic information determining factors Vlll and lX is defective, hemophilia results. As a result, the protein factors needed for normal blood clotting are effected. In males, the single X chromosome can not compensate for the lack, and will show the defect. In fe