The most common and most likely answer to this crossword clue is the 8 letter word NURSLING
I've seen this crossword clue in Financial Times
N
U
R
S
L
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More clues leading to the result NURSLING
Buddy explains!

The straight part
We know that "young child" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case young child = nursling.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NURSLING mean?
NURSLING noun- A young child or animal being nursed.