When it's gone far beyond not getting along and the knives are out

Does not include switched at birth or stolen identity stories those are on my other lists

Switch Switched children the most comprehensive list of its type. Covers children that were switched lost stolen or had their identities somehow taken

https://www.novelupdates.info/viewlist/24775/?st=1

My other lists can be found here https://www.novelupdates.info/user/231781/kawaii12345/
and include

Lost And Found Children

Switch Real Children VS. Fake Children (children coming to terms with being switched)

Fake Children vs Real Children Quick Transmigration
Real Child vs Fake Child Standalone list
Sibling Warfare (when the kids are about to kill each other)
Poisonous Families
Transmigrated into a novel
ACT: Ancient China Transmigration