Important question of the elder offspring? (5,5)

I believe the answer is:

major issue

I'm a little stuck... Click here to teach me more about this clue!

'the elder offspring?' is the definition.
The definition suggests a singular noun which matches the answer.

'important question' is the wordplay.
'important' becomes 'major' (major can mean of great importance).
'question' becomes 'issue' (I've seen this before).
'major'+'issue'='MAJOR ISSUE'

'of' is the link.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.