Biological duplicate (5)
I believe the answer is:
clone
'biological duplicate' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for clone that I've seen before include "spit" , "Identical copy" , "Organism reproduced asexually from one ancestor, like Dolly the sheep" , "Person resembling someone else" , "Exact replica" .)