To further clarify, this series is following Claremont's original concept for Sabretooth, which was that he was Wolverine's father. That's why he wants to get revenge on Wolverine's killers and why he now feels he and Kitty are connected. He doesn't think she's literally related to him, just that she has part of his son within her.
I'm surprised those things jumped out at you but not that Storm was a little girl.