# The Book — A Complete Working Document
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## The Premise
On the day a child is born, the world divides into two identical copies. In one world the child is male. In the other, female. Everything else — the genome, the city, the parents, the quality of the light coming through the hospital win…
# The Book — A Complete Working Document
---
## The Premise
On the day a child is born, the world divides into two identical copies. In one world the child is male. In the other, female. Everything else — the genome, the city, the parents, the quality of the light coming through the hospital window — is identical.
The only variable is the chromosome.
This is what that difference made.
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## The Central Argument
The book is not about gender as ideology or politics. It's about something m