I have been thinking about this.... but hope that from all possibility Kishimoto won't chose something like this:
Somehow Karin overwrotte either Sasuke's or Sakura's DNA like a virus and Tada, Sarada came! The worst of all that if Sasuke's DNA was overwritten - which is more possible due Orochimaru and her "healing jutsu" -, then Sarada is Sakura's AND Karin's daughter, Sasuke was just an infected donor of Karin.
Don't worry, this was just a mind**** fake theory, don't take it seriously.! XD
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Somehow Karin overwrotte either Sasuke's or Sakura's DNA like a virus and Tada, Sarada came! The worst of all that if Sasuke's DNA was overwritten - which is more possible due Orochimaru and her "healing jutsu" -, then Sarada is Sakura's AND Karin's daughter, Sasuke was just an infected donor of Karin.
Don't worry, this was just a mind**** fake theory, don't take it seriously.! XD