This may explain Sarada ...

[Ensifer]

If the rumored spoilers from Evil's sources are to be correct, then this may be one of the many reasons of Sarada's conception, anything is possible in the world of Naruto I suppose ...

Spoiler

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We know how Karin can be, especially when Sasuke is vulnerable.

 

[Angelic.]

sasukes such a noob he couldnt protect himself

 

[~Ethereal~]

I see.

 

[Naruto X Hunter]

But we know he left to fight Itachi right away.

 

[LaSalada]

Karin somehow aquires Sasuke's genetics to produce Sarada in the hopes she can lure Sasuke into her life?

Sasuke refuses to accept Karin but ends up keeping Sarada anyway?

I really hope its something like that for the sake of Sasuke and Sakura's characters.