Cock-up over character without children (4,5)

I believe the answer is:

sine prole

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'without children' is the definition.
I can't tell whether this definition defines the answer.

'cock-up over character' is the wordplay.
'cock-up' becomes 'penis' (I can't justify this - if you can you should give a lot more credence to this answer).
'over' is a reversal indicator.
'character' becomes 'role' (synonyms).
'penis' backwards is 'sinep'.
'sinep'+'role'='SINE PROLE'

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I've seen this clue in The Guardian.

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