Keen on men and women, soldiers petition magazine (3,5)
I believe the answer is:
big issue
'keen on men' is the definition.
The definition suggests a singular noun which matches the answer.
'women soldiers petition magazine' is the wordplay.
I cannot really understand how this works, but
'soldiers' could be 'gis' (GI is an informal term for a US soldier) and 'gis' is present in the answer.
'petition' could be 'sue' (both can mean to appeal or ask for something) and 'sue' is found within the answer.
The remaining letters 'bi' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for big issue that I've seen before include "The -- --, street newspaper" , "paper" .)