What kind of doctor knows most about causes of female sexual dysfunction?

Any specialty: Diagnosis & treatment of female sexual dysfunction is not limited to one medical/surgical specialty, at least not currently, as the field is still in its infancy. As such, you're just as likely to find family physicians, general internists & gynecologists, etc who focus their practice on fsd. Complicating this is the fact that there is no recognized board or certification. So best to ask around.

Sex Therapists: Sex therapists who are highly qualified can be certified through an organization called AASECT. These professionals receive well over one hundred hours of training and supervision in their field. You can find an AASECT certified sex therapist at www.aasect.org