Present journal containing conclusion to report handed down (10)
I believe the answer is:
hereditary
'handed down' is the definition.
(thesaurus)
'present journal containing conclusion to report' is the wordplay.
'present' becomes 'here' (both can mean in attendance).
'journal' becomes 'diary' (diary is a kind of journal).
'containing' is an insertion indicator.
'conclusion to' indicates one should take the final letters.
The last letter of 'report' is 't'.
'diary' going around 't' is 'ditary'.
'here'+'ditary'='HEREDITARY'
(Other definitions for hereditary that I've seen before include "passed down through generations" , "passed from generation to generation" , "Ancestral" , "Passed on by genetic factors" , "Family" .)