The marital issue? (5)
I believe the answer is:
child
'issue?' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for child that I've seen before include "Youngster" , "Infant" , "Immature, irresponsible person" , "Young person" , "Baby" .)