Hemophilia is a sex-linked recessive disorder. This means that only one allele recessive allele for the trait in males will cause the disease to occur in males. However, for females, there should be two recessive alleles present for the gene for the trait to occur. A female carrying one recessive allele for the trait will be a carrier.
If a father is hemophiliac, this will mean that all the daughters will be carriers for the disease as they will have one of the allele for the trait from the father. On the other hand, about half of the sons will have the disease if they get the recessive allele from the father for the trait.
