Manar Maged was born with two heads. The second has a brain, but no body. Despite this, the second head shows signs of independent consciousness - blinking, smiling, crying. It even tries to suckle. Worringly, Manar's second head is also a parasite and is slowly killing her. This condition, called craniopagus parasiticus, has only been recorded 10 times in medical history. Neurosurgeon Professor Lotvi has pioneered a technique to prevent the bleeding common in surgery on twins conjoined at the head. Bodyshock details the operation needed to save Manar's life.

A Swiss doctor discovered these tiny, fragile children in a remote Indian village in 2003. Their bones were dissolving and their hair thining and he diagnosed them with progeria, a rare disease that uncontrollably accelerates its sufferers into old age. Even relative to what is already known about the disease, the children remain a medical mystery. One mother had given birth to five children who had been affected, despite an established average of one sufferer in every 4 million births.

Weighing the same as five baby elephants and a shade less than a Mini Cooper, Patrick Deuel is one of the heaviest men ever - and a medical miracle. His heart and other organs should have collapsed long before he reached his record-breaking weight of 76 stone 8lbs. Patrick has been lifted through a removed wall and taken to hospital in a reinforced ambulance, put on a diet and given a gastric bypass operation. Once home again, he must decide whether he wants to live - or to continue eating himself to death. Rosalie Bradford, who was once one of the world's fattest women, lost an incredible 900 pounds only after she realised that her food addiction was a reponse to childhood neglect. Bodyshock looks at both of these stories, and the growing number of people who appear to be eating themselves to death.

With her legs fused together like a tail, Milagros Cerron has one of the rarest birth abnormalities in the world: sirenomelia, or 'mermaid syndrome'. Can an operation by charismatic but controversial plastic surgeon Dr Luis Rubio, to be broadcast live on national television, save this little Peruvian girl? The story of the operation and the attendant media circus is a revealing look at what happens when medicine, politics, religion and superstition collide in a poor and struggling country.