The most common and most likely answer to this crossword clue is the 14 letter word BROTHER-GERMAN
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Buddy explains!
The straight part
We know that "Sharing parents each may be the other’s" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sharing parents each may be the other’s = brother-german.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 BROTHER-GERMAN mean?
BROTHER-GERMAN noun- A full brother: a brother born to the same mother and father, as distinguished from half-brothers (uterine brothers), step-brothers, or 'brothers' established through relationships such as wardship.