A stable parent? (4)
I believe the answer is:
sire
'a stable parent?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sire that I've seen before include "Foal's father" , "Rise for male parent (4)." , "Make children" , "Stallion; beget" , "Male parent of an animal" .)