bbhope - my husband has Sertoli cell only syndrome. He does not have undescended testes, or any other apparently problem. There is usually no known reason for Sertoli cell only - they have not yet discovered what causes it.
I can't remember where you are, but yes I definitely recommend seeing a urologist. Dr Golovsky (in Sydney) was the most useful doctor we saw. He's really the expert & has done a lot fo work in this area. I wish you good luck.