On September 3rd 1973, at 6:28pm and 32 seconds, a bluebottle fly capable of 14,670 wing beats a minute landed on Rue St Vincent, Montmartre. At the same moment, on a restaurant terrace nearby, the wind magically made two glasses dance unseen on a tablecloth. Meanwhile, in a 5th-floor flat, 28 Avenue Trudaine, Paris 9, returning from his best friend’s funeral, Eugène Colère erased his name from his address book. At the same moment, a sperm with one X chromosome, belonging to Raphaël Poulain, made a dash for an egg in his wife Amandine. Nine months later, Amélie Poulain was born.