Important subject, children (5)
I believe the answer is:
issue
I believe this is a double definition.
'important subject' is the first definition.
(I've seen this before)
'children' is the second definition.
(thesaurus)
(Other definitions for issue that I've seen before include "One of a series published periodically" , "Topic (to be addressed)" , "Publish, bring out" , "Come forth or bring out" , "Children, offspring" .)