Draw conclusion from About a Boy (6)
I believe the answer is:
reason
'draw conclusion' is the definition.
'about a boy' is the wordplay.
'about' becomes 'rea' (I've seen this in other clues).
'a boy' becomes 'son' ('son' can be a synonym of 'boy'**).
'rea'+'son'='REASON'
'from' is the link.
(Other definitions for reason that I've seen before include "Mental power to justify an act" , "Motive or right thinking" , "Reach logical conclusions" , "Explanation for some event" , "Power of thought" .)