Come on, do you guys honestly believe that Karin is Sarada's mother? When Gaiden was first announced, do you remember that there were released sketches of Sasuke and Naruto's families?
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Why would they make such sketch about Sasuke's family, if Sakura isn't the mother of his daughter? Also, how come Naruto didn't know that Sarada isn't Sakura's daughter? It implies that he saw Sakura pregnant and knew that she's Sarada's mother. Pregnancy is for 9 months, it's either he lied to Sarada and Suigetsu that he didn't know, or he didn't see Sakura for the whole 9 months of her pregnancy. In fact, it was neither, he didn't lie to them, because he saw Sakura pregnant with Sarada and was shocked to hear that. So the point is, that Karin was collecting Sasuke's stuff for a while, it's plausible she was the one who helped Sakura with the birth since no birth records were kept in Konoha and it was Sarada's umbilical cord that Suigetsu used for the DNA test. Get ready for next (or possibly the 10th) chapter's plot twist when they meet up with Sakura and have a family chat. ^^
Hahaahaha Ask Sasuke Schmosby who is the Mother. Hahahaah
Consider this. Sarada goes on a journey to look for her real mom. She has already learned that bonds>>Blood
1. She learns that Karin is her real mom. Then what? Nothing more. Bonds >> Blood. Somehow Sakura still is as important to Sarada the way Karin will be to her.
2. She learns Sakura is her real mom and that she shouldnt have doubted. See? Bonds+Blood. Sakura wins everything.
Who would offer the more decent drama, Karin or Sakura?
Those who answer that Karin would is just plain stupid.