With 18 million residents in los Angeles, Orange, Kern, San Bernardino, Santa Barbara, San Luis Obispo, Riverside and Ventura Counties, and based upon Centers for Diesease Control and Prevention estimates of one Hemophilic male per 5000 live male births, there are an estimated 1800 males in the HFSC's catchment area with Hemophilia A and B.

In 2002, HFSC's constituants continued to reflect the catchment area: