The book follows a chronological structure, exploring how the brain develops and eventually declines:

The narrative moves into the "puber brain," exploring the biological roots of aggression, love, and addiction. Swaab suggests that even religious beliefs are "imprinted" on the brain in early development, much like a native language.

Swaab argues that many of our traits, including sexual orientation, gender identity, and predispositions to disorders like ADHD or autism, are "hard-wired" during pregnancy through a combination of genetics and hormonal exposure.

The "story" concludes with the breakdown of the brain, focusing on neurodegenerative diseases like Alzheimer's and Parkinson's, as well as the biological reality of near-death experiences. Key Takeaways from the First Edition (2010) Reviews - Wij zijn ons brein: van baarmoeder tot Alzheimer

A central theme is the provocative claim that free will is an illusion . Swaab presents evidence that our choices are actually the result of predetermined neuronal circuits and chemical processes.