Give children a little portion of kidneys (5)
I believe the answer is:
renal
'of kidneys' is the definition.
(I've seen this before)
'give children a little portion' is the wordplay.
'portion' says the answer is hidden in the clue (I've seen 'portion of' mean this).
'RENAL' is hidden in the letters of 'give children a little'.
(Other definitions for renal that I've seen before include "like kidneys" , "Pertaining to the kidneys" , "using the reins" , "Vital organ's" , "Concerning the kidneys" .)