15X-23 is NOT a clone
This one might surprise a lot of people since X-23 is often referred to as Wolverine’s clone, but that’s a common misconception. According to her origin story, described in the “Innocence Lost” arc, she is actually a genetic double. Prior to X-23’s birth, there had been 22 failed cloning
The scientist who was brought on to correct this error, Sarah Kinney, discovered that there was a problem with the DNA sample. In short, there was an issue with the Y chromosome that resulted in the clones dying. In order to correct this error, she proposed the use of two X chromosomes resulting in the creation of a female clone. She pointed out that this would not be a true clone, but a genetic duplicate. However, the duplicate would still have Wolverine’s abilities. Her superiors rejected this idea insisting on a male clone, but she began the project in secret. Once it was discovered, her bosses allowed her work to continue, but forced her to serve as the surrogate for the child’s birth.