Doubting Scotsman, perhaps, following female medical expert (13)
I believe the answer is:
diagnostician
'medical expert' is the definition.
(someone who makes diagnoses)
'doubting scotsman perhaps following female' is the wordplay.
'doubting' becomes 'agnostic' (someone unsure on the topic of religion).
'scotsman perhaps' becomes 'Ian' (common Scottish name).
'following' says to put letters next to each other.
'female' becomes 'di' (short for Diana).
'agnostic'+'ian'='agnostician'
'agnostician' put after 'di' is 'DIAGNOSTICIAN'.
(Other definitions for diagnostician that I've seen before include "Vet, perhaps" , "disease expert" , "he may identify your problem" , "Identifier of illnesses" , "doctor" .)