First of six programmes examining the human side to scientific discoveries.

Eight-year-old Rachel [text removed] suffers from a rare and severe form of epilepsy, which transforms her warm and loving personality into a violent and aggressive one. She suffers as many as five fits a day and drugs can make her worse. Rachel's parents must decide whether to allow a surgeon to change her life by removing half her brain.
See today's choices.
(Digital widescreen)