Plastinated human bodies in a position simulating sexual intercourse are seen at the "Body Worlds" exhibition by Gunther von Hagen at the Universum Museum in Mexico City August 14, 2012. Von Hagen is a German anatomist who invented plastination, the method for preserving biological tissue specimens. The exhibition shows whole bodies plastinated in lifelike poses and dissected to show various structures and system of human anatomy. REUTERS/Henry Romero (MEXICO - Tags: SOCIETY SCIENCE TECHNOLOGY) 

Polymer preserved foetuses are displayed at the Bodies exhibition at Earl's Court in London April 12, 2006. The exhibition, which is designed to allow visitors an insight into what lies beneath their own skin, showcases 22 whole body specimens and more than 260 organs and partial body parts. REUTERS/Kieran Doherty 

A polymer preserved skull is displayed at the Bodies exhibition at Earl's Court in London April 12, 2006. The exhibition, which is designed to allow visitors an insight into what lies beneath their own skin, showcases 22 whole body specimens and more than 260 organs and partial body parts. REUTERS/Kieran Doherty 

A polymer preserved body is displayed at the Bodies exhibition at Earl's Court in London April 12, 2006. The exhibition, which is designed to allow visitors an insight into what lies beneath their own skin, showcases 22 whole body specimens and more than 260 organs and partial body parts. REUTERS/Kieran Doherty 

A polymer preserved foetus is displayed at the Bodies exhibition at Earl's Court in London April 12, 2006. The exhibition, which is designed to allow visitors an insight into what lies beneath their own skin, showcases 22 whole body specimens and more than 260 organs and partial body parts. REUTERS/Kieran Doherty 

A polymer preserved foetus is displayed at the Bodies exhibition at Earl's Court in London April 12, 2006. The exhibition, which is designed to allow visitors an insight into what lies beneath their own skin, showcases 22 whole body specimens and more than 260 organs and partial body parts. REUTERS/Kieran Doherty 

Luigi Vescovi (Top L), codirector of the San Raffaele Hospital's Stem Cell Research Institute in Milan, poses with scientists Giulio Cossu (Top R) and Rossella Galli in a Institute's laboratory September 19, 2000. [Scientist in Milan said they had shown that stem cells from the brains of adult rats can be used to generate muscular tissue in a discovery that could eventually have implications for transplant therapy. Vescovi said in a news conference that new research had proven what he called the transdifferentiation capacity of somatic adult stem cells. Its a process by which a cell from a given tissue can give rise to a cell form of a different tissue, possibly even of a different embryonic origin, he told Reuters after presenting a paper to be published in science journal Nature Neuroscience. ] 

Luigi Vescovi (Top L), codirector of the San Raffaele Hospital's Stem Cell Research Institute in Milan, poses with scientists Giulio Cossu (Top R) and Rossella Galli in a Institute's laboratory September 19, 2000. Scientist in Milan said they had shown that stem cells from the brains of adult rats can be used to generate muscular tissue in a discovery that could eventually have implications for transplant therapy. Vescovi said in a news conference that new research had proven what he called the transdifferentiation capacity of somatic adult stem cells. Its a process by which a cell from a given tissue can give rise to a cell form of a different tissue, possibly even of a different embryonic origin, he told Reuters after presenting a paper to be published in science journal Nature Neuroscience.

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