'By reconstructing how our body plans first sprang into existence or by remaking the structural origins of our complex brains, researchers can use these models to repeatedly probe the enigmatic biological foundations of our sense of self. These foundations include not just the orchestrated patterning of our bodies as the human form first arises, but also the self-organization of the brain itself, the physical seat of all our thoughts, feelings, and consciousness. Paradoxically, in the process of illuminating these biological mysteries, human stem-cell-based modeling could recast much of what we take to be special about ourselves as simply a reproducible series of physical events. What does it mean for individuality, for example, if the early embryonic history of each cell line donor can be replayed again and again through the artificial generation of identical human embryo models?'
