Hemophilia is a disorder in the way the clotting factor VIII or IX is made by the body. The genes that control this process are found in the X-chromosome.
Males have one X-chromosome and one Y-chromosome while females have 2 X-chromosomes.
If a man who has hemophilia were to have a female offspring with a woman who does not have hemophilia, the probability of the girl child having hemophilia is zero.
As the offspring receives the X-chromosome from her father which has the hemophilia gene and another X-chromosome from the mother that is normal, the daughter will be a carrier of hemophilia.
Carriers of hemophilia can make enough of the clotting factor to avoid serious bleeding that is associated with hemophilia, though around 50% of carriers have a slightly increased risk of bleeding.