Board Thread:Naruto Discussions/@comment-26320097-20150423120614/@comment-5551986-20150613073847

Sakura is probably infertile or incapable of having children and Sasuke and Sakura could have both used Karin as a surrogate mother for a few reasons, one, she is an Uzumaki with good genes and due to her regenerating having a high chance of surviving child birth, she was close to sasuke, isn't ugly and Sasuke might have wanted his daughter to be potentially stronger by mixing both Uzumaki and Uchiha DNA. This explains why Karin is her biological mother, how Sakura is also still kind of her mother.

Besides even when Naruto stated that she has Sakura's personality I was doubtful she was her biological mother because personality can also change by just being around and being influenced by certain individuals. Besides, Sakura nor her mother or father wore glasses, neither did sasuke, his mother or father, so inherently she should biologically possesses pretty decent eyesight.