Board Thread:Naruto Discussions/@comment-26320097-20150423120614/@comment-24357950-20150626123133

Namida12 wrote: hm... if Karin is Sarada's mother, why did she give her daughter to Sakura? and Sasuke also mention that Sakura is his wife right? so here's what I've got so far: Karin = Sarada's mother Sarada = Sasuke's daugther Sasuke = Sakura's husband Sakura = Sarada step mother why is Sasuke married Sakura if Sarada is Karin and his daugther? o_o now I really confuse, and one of my friend told me that in a character profile to the new movie, it says that Sarada is SasuSaku Daugther (I don't know if it were true or not, I haven't check it yet)

Could have many reasons. The mistake in your idea is that you're assuming that Sarada was a love child. But who says there was any romantic interaction between Sasuke and Karin? Karin could have as well just been an egg donor to Sakura or the surrogate mother.