The surprising facts and phenomena of the human body are expounded here by popular science presenting duo the van Tulleken twins.

Chris van Tulleken trained in medicine in Oxford and is a Member of the Royal College of Physicians. He has a diploma in Tropical Medicine from the London School of Tropical Medicine and after more than a decade working in the NHS he is now doing a PhD in Molecular Virology under the supervision of Greg Towers at UCL.

Xand van Tulleken has a diploma in Tropical Medicine, a Diploma in International Humanitarian Assistance and a Master's in Public Health from Harvard, where he was a Fulbright Scholar. He is a contributing editor to the first edition of the Oxford Handbook of Humanitarian Medicine and has worked for Doctors of the World, Merlin and the World Health Organisation in humanitarian crises around the world.

Chris and Xand have worked on a number of projects together, including Operation Ouch!, a 2x BAFTA-winning children's health show on CBBC. Additionally, the two have collaborated on Horizon: Fat vs Sugar, Horizon: Is Binge Drinking Really That Bad for You?, The Secret Life of Twins and Operation Ouch: Blow Your Mind. And in their younger and slightly fuller-haired days, Chris and Xand starred in a series called Medicine Men Go Wild, a show in which they did, in fact, go wild.

Andrew Cohen is Head of the BBC Science Unit and the Executive Producer of the BBC series Secrets of the Human Body. He has been responsible for a wide range of science documentaries including Horizon, the Wonders trilogy, Stargazing Live and Human Universe. He lives in London with his wife and three children.