A fresh perspective on autism research with the developing "Bacterial Theory" of autism. The fastest-growing developmental disorder in the industrialized world, autism has increased an astounding 600 per cent over the last 20 years. Science cannot say why. Some say it's triggered by environmental factors and point to another intriguing statistic: 70 per cent of kids with autism also have severe gastrointestinal symptoms. Could autism actually begin in the gut? The Autism Enigma looks at the progress of an international group of scientists who are studying the gut's amazingly diverse and powerful microbial ecosystem for clues to the baffling disorder.