| ICD10 = - | ICD9 = | ICDO = | OMIM = 306700 | OMIM_mult = | MedlinePlus = 000537 | eMedicineSubj = med | eMedicineTopic = 3528 | MeshID = D025861 }} Haemophilia or hemophilia (from Greek haima "blood" and philia "to love") is the name of a family of hereditary genetic disorders that impair the body's ability to control blood clotting, or coagulation. In the most common form, haemophilia A, clotting factor VIII is absent. Hemophilia B, also known as factor IX deficiency, is the second most common type of hemophilia, but Hemophilia B is far less common than Hemophilia A, occurring in about one in 25,000 male births. The effects of this sex-linked, X chromosome disorder are manifested almost entirely in males, although the gene for the disorder is inherited from the mother. In about 30% of cases of Hemopilia B, however, ther