Health Conditions

What are the risk factors?

About two-thirds of all individuals with hemophilia have inherited it, whereas the other one-third of the cases have no family history of the condition. These individuals are believed to have had a genetic alteration (mutation) during the time their body organs and systems were forming before birth. The exact causes of such mutations are unknown.

If hemophilia is inherited, the likelihood that a child will have hemophilia or be a carrier is well-established.

• A boy whose mother is a carrier has a 50:50 chance of having hemophilia, whether or not his father has hemophilia.
• A boy whose mother has hemophilia, but whose father does not, will have hemophilia.
• A boy whose mother is not a carrier but whose father has hemophilia has no chance of either having hemophilia or being a carrier.
• A girl whose mother is a carrier and whose father does not have hemophilia has a 50:50 chance of being a carrier.
• A girl whose father has hemophilia will definitely be a carrier, whether or not her mother is a carrier.
• A girl whose mother is a carrier and whose father has hemophilia will either be a carrier or have hemophilia.
• A girl whose mother has hemophilia but whose father does not, will be a carrier.
• If both parents have hemophilia, all their children will have hemophilia, as well.