Hemophilia is a rare genetic disorder in which the blood does not clot properly, leading to excessive bleeding and bruising. It is usually inherited and primarily affects males. Hemophilia is caused by a deficiency in clotting factors in the blood, specifically factor VIII (hemophilia A) or factor IX (hemophilia B). Symptoms of hemophilia can range from mild to severe, and treatment typically involves replacing the missing clotting factor through injections or infusions.