>Do newborns have a standardized brain structure?
No.
Genetic diversity due to isolation of cultures in their environments over the eons has made this impossible.
No.
Genetic diversity due to isolation of cultures in their environments over the eons has made this impossible.
The differences between unrelated newborns would be both genetic & environmental, compared to the identical genetics and nearly identical environments of the twins.
From which point all would begin to diverge further.