Hemophilia is a rare genetic bleeding disorder that primarily affects males. People with hemophilia do not have enough of, or are missing, one of the blood clotting proteins normally found in blood. Two of the most common forms of hemophilia are A and B. In people with hemophilia A (also called classic hemophilia), clotting factor VIII is deficient or absent. In people with hemophilia B (also called Christmas disease), clotting factor IX is deficient or absent. People with hemophilia do not bleed more profusely or bleed faster than normal; they bleed for a longer period of time. In most cases, there is a family history (it is a hereditary disorder), but in as many as 30% of cases, there is no family history of hemophilia. In these cases, the mother may not be aware that she carries the gene for hemophilia, or a gene mutation may have occurred spontaneously.