To be fair this question may be a bit difficult. I believe that you are perfectly capable. Hemophilia is described as a Genetic condition which causes a deficiency of a factor that produces the anticoagulant component of the blood; Platelets. This condition usually means that the body is unable to clot efficiently, and so excessive bleeding are possible for even the most minor of bleeding injuries, it can be so severe that blood is often transplanted into a hemophiliac.
Now that you have a background, you may understand several things. Genetic conditions are not contagious or are able to be passed down. Since the condition only affects platelet formation, the other parts of the blood and the blood itself are perfectly capable of being used (the receivers body will eventually produce normal platelets). Hence why there should not be a problem for you donating blood to someone.
However the affects on yourself is the main issue. A hemophiliac because he lacks effective platelets will bleed profusely for minor bleeding injuries. People with hemophilia should be aware that most places may not want to draw blood from those affected with this blood disorder, just because it can pose a liability if the donor bleeds out.
Ultimately I would just first check in with the people who set up the donation, as well as a hematologist, before someone with hemophilia considers getting blood donated..
