Hemophilia mostly affects men. A woman may be a carrier of the gene that causes hemophilia but usually will not have any signs or symptoms of the disease. If a woman is affected by hemophilia, the symptoms are usually very mild. Hemophilia can affect a person of any race, although most people with the condition are white.

Approximately 1 out of every 5,000 male babies is born with hemophilia A, while 1 out of every 30,000 male babies is born with hemophilia B.¹