I saw this surrogacy theory of Sakura being unable to conceive (some feel because of Madara stabbing her) and hence Sasuke and Sakura approaching Karin for having a kid on gamefaqs,youtube and somewhere in NF.Personally I am completely against this because
1.Sasuke was never that worried or desperate about having a kid to go to this extent of using another woman outside his family
2.Even though SS is married,SK is still the MVP here because in the end when all's said and done,SK not only has the kid and there are certain moments in the manga where Sasuke did show care for Karin so the SS marriage just seems like a mere formality Kishi did to appease a fandom
3.This kind of shit never happens in shonen especially with the family of one of the MCs
4.Its also slightly ironic in that one of the top medical ninjas with byakugou is unable to fully repair the damage caused to her internals
1.Sasuke was never that worried or desperate about having a kid to go to this extent of using another woman outside his family
2.Even though SS is married,SK is still the MVP here because in the end when all's said and done,SK not only has the kid and there are certain moments in the manga where Sasuke did show care for Karin so the SS marriage just seems like a mere formality Kishi did to appease a fandom
3.This kind of shit never happens in shonen especially with the family of one of the MCs
4.Its also slightly ironic in that one of the top medical ninjas with byakugou is unable to fully repair the damage caused to her internals