Book excerpt: When we are born, we are each assigned a gender based on our physical anatomy. But why is it that some people experience such dissonance between their biological sex and their inner identity? Is gender something we are or something we do? Is our expression of gender inborn or does it develop as we grow? Are the traditional binary male and female gender roles relevant in an increasingly fluid and flexible world? This intelligent, stimulating volume assesses the connections between gender, psychology, culture and sexuality, and reveals how individual and social attitudes have evolved over the centuries.