USCIS issued a new policy memorandum last month which alters the policy regarding the agency's accomodation of religious concerns during the biometrics process. For photographs, USCIS will accomodate religious headwear if a "reasonable likeness" of the face can be obtained. The full face must be visible and the religious headwear cannot cast a shadow on the face. If USCIS asks for religious headwear to be removed, they are supposed to offer a private room for photographing and to provide a same-sex photographer if possible.
A similar approach is now in place with regard to fingerprinting. Because fingerprinting frequently involves touching between the technician rolling the prints and the individual, same sex technicians are to be provided if possible.