• The prevalence of females with severe or moderate hemophilia A or B in the United States. [ Designated as safety issue: No ]
  

• Collect existing data on the genetic and/or chromosomal causes for severe and moderate hemophilia A and B in females in the United States. [ Designated as safety issue: No ]
  
• To determine the natural history of hemophilia in females by collecting and analyzing data on the symptoms, treatment patterns, and complications of hemophilia in this cohort. [ Designated as safety issue: No ]
  
• Collect and analyze data on the health-related quality of life and psychosocial adaptation to disease of females in the United States. [ Designated as safety issue: No ]
  

This study is designed as an epidemiological study with retrospective clinical and genetic data collection and prospective quality of life (QOL) data collections and genotyping of subjects without current molecular diagnosis. Data on the genetic/chromosomal etiology of the condition will be collected through chart review. For those subjects who have not had molecular or cytogenetic analysis, molecular and cytogenetic testing will be offered after genetic counseling. Those subjects who agree to have genetic testing will have 5-10 ml of blood drawn and sent to the cytogenetic laboratory at Weill Cornell Medical College for testing to determine the chromosomal complement, and 5 ml of blood sent to Dr. Arupa Ganguly at the University of Pennsylvania for the identification of a factor VIII or factor IX mutation, and X-chromosome inactivation studies.