The most common and most likely answer to this crossword clue is the 10 letter word STRIPLINGS
I've seen this crossword clue in Financial Times
S
T
R
I
P
L
I
N
G
S
Buddy explains!

The straight part
We know that "Youths" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case youths = striplings.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.
Crossword Answer definitions
STRIPLINGS noun- (sometimes humorous) A youth in the state of adolescence, or just passing from boyhood to manhood; a lad. .
- A seedling with most of the leaves stripped off.