Are you so sure that questioning your diagnosis means a questioning the professionalism of the diagnosing doctor? One does not imply the other. My own T has begun to question my diagnoses. This seems only natural though. After all, she spends an hour with me every week while I only see my psychiatrist every three months. For her to consider other possibilities seems only to be expected. What she is talking about now represents no distaste or fear for me. I don't foresee any negative implications. But, could your own discomfort with new possibilities be on account you are uncomfortable with the implied diagnoses? Is there some sort of negative consequence you are apprehensive of to a change in diagnosis? Honestly, I don't feel it will be at all earth shattering. I think you owe it to yourself to discuss this further with your therapist. I believe you actually have gains to be made out of a frank conversation. This gives you the opportunity to get involved and give the points raised some critical thinking - always something positive.