Thanks for not smacking me!

I see your logic but I think we're comparing apples and oranges. I think if a female patient feels they will be better helped with a female dr. and vice versa, then they will.
In therapuedic realtionship the main ingredient for success is trust, IMHO.
Also, the therapist has to guide the patient to growth without being obvious. Hard to do if the patient is out-thinking the therapist.