Faces of kids specially are unbelievable to be generated. Their backgrounds, clothes, hair facial expressions seem all very unique to that picture. I will be going through the dataset to find the matches once they release it.
Neural networks basically learn to implement nearly arbitrary computations (up to a certain circuit depth) to produce the desired output, so you can also think of deep learning as program mining of a certain program space that is reachable by the adaptive functions in a neural network. Stephen Wolfram has written about that in his blog and talked about it in one of his podcasts. So it's basically magic much like evolution, and it will probably destroy us because it's simply too powerful.
[0] https://twitter.com/phillip_isola/status/1066567846711476224
If you go through the generated faces you can see all of them have different background. These are not generated from scratch, only picked from memory to match the requirements.
Each face has totally different hair and hairstyle.
Have the published the training dataset?