Son getting drunk must be examined (7)
I believe the answer is:
scanned
'examined' is the definition.
(scanning is a kind of examining)
'son getting drunk' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'getting' says to put letters next to each other.
'drunk' becomes 'canned' (canned can mean drunk).
's'+'canned'='SCANNED'
'must be' is the link.
(Other definitions for scanned that I've seen before include "Glanced over" , "given thorough examination" , "examined closely" , "Thoroughly examined" .)