Inheritance

Haemophilia is an inherited condition. However, it is possible for the condition to appear in any family.

It is thought that at least 30% of people with haemophilia have no family history of a bleeding disorder. It is difficult to be exact about this because of the way in which haemophilia is inherited.

Technically, it has a “sex linked recessive" inheritance pattern. This means that while generally only males are affected by the condition, it is passed on through the female member of the family.

When the father has haemophilia, but the mother does not, none of their sons will have haemophilia, however all of their daughters will be obligate carriers, carrying the haemophilia gene. His sons will not be affected by haemophilia, nor will they be “carriers".