I'll spill:
So far this entire gaiden has focused on the biological relation between a mother and her child. This lady in the photo, she has the same glasses as me, is she my real mother?( I don't even want to know the logic behind that statement) The DNA test tells me your not my real mother!
Shin goes on about how children are nothing more than a way for genes to continue to exist. The connection between a parent and child is painted as one that is purely biological, to ensure the survival of the fittest. Is that what a child really is, a way for a species to continue or is there more?
Kishimoto has said that the Naruto manga has always been about connections/bonds. This new series he wants to:
write on elements such as the concrete DNA of those who are connected, and their feelings
those who are connected are the same. In contrast to a DNA connection, what has been inherited, and how?
What does Sakura say, in response to Shin? "You have no idea what it means to be a parent and what humans hold dear.."
Sakura is Sarada's biological mother but thats not the point, thats not the reason Sarada thinks of Sakura as her "mama" or Sakura thinks of Sarada as her "beloved daughter". They are mother and daughter due to the emotional bond they share not due to their biological bond.