Madness for international organisation to be concerned with a child (8)
I believe the answer is:
unreason
'madness' is the definition.
(I've seen this in another clue)
'international organisation to be concerned with a child' is the wordplay.
'international organisation' becomes 'UN' (United Nations).
'to be concerned with' becomes 're' (re means regarding a certain topic).
'child' becomes 'son' (male child).
'un'+'re'+'a'+'son'='UNREASON'
'for' is the link.
(Other definitions for unreason that I've seen before include "foolishness" , "insanity" , "The absence of rationality or logic" , "Irrationality" , "nonsense" .)