Sex object accepted by good queen (6)
I believe the answer is:
gender
'sex' is the definition.
(I know that sex can be written as gender)
'object accepted by good queen' is the wordplay.
'object' becomes 'end' (I've seen this in other clues).
'accepted by' is an insertion indicator (inserted letters are accepted).
'good' becomes 'g' (abbreviation).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'g'+'er'='ger'
'end' going inside 'ger' is 'GENDER'.
(Other definitions for gender that I've seen before include "Sex category" , "What divides males and females" , "Masculine, feminine or neuter" , "Sexual status" , "Man or woman" .)