...Or at the very least there isn't a direct genetic loop. Think about it for moment. C!Syaoran and C!Sakura died and reincarnated in another world before they had R!Syaoran as their son, right? But they had to be physically born into that world somehow and R!Syaoran mentions several times that the Fuhitaka of the real Clow Country resembles his gramdpa, Nadeshiko his grandma, etc, so it's hardly a leap to assume that C!Syaoran was born to his Cardcapter Sakura-esk parents as well; meaning that while C!Syaoran is the direct father of R!Syaoran who he eventually gets cloned off, there is no reason to assume he still has the same 'Sakura is my mother genetics' by the time he and C!Sakura eventually have their child.