Solution for 15 May cryptic crossword clue

Children – an important subject (5)

Solution – issue

This is an example of a double definition clue.  

Here “issue” can be another word, somewhat archaic, for someone’s children.  An issue can also refer to a point of contention or debate.

I like the way that the whole clue could be read to be a statement about children – who are indeed subjects of importance.