I'm curios re those who think it is........why?
I know this is old, but I wanted to chime in.
Virtually ALL of the scientific evidence regarding the Shroud of Turin (with the exception of the carbon dating) indicates it is authentic. In addition, it has been proven (as published in the peer reviewed scientific journal
Thermochimica Acta) that the section of the cloth used for carbon dating was from a medieval repair. Thus the reason for the medieval date.
Despite the myriad of tests done on the Shroud, no one has been able to figure out how the image got there. There are some definitive conclusions that can be drawn however.
First, the image is NOT a painting and this is firmly established.
Second, where there is blood (and it is real blood) there is no image, meaning that the blood had to be on the cloth before the image.
Third, the cloth covered a dead body that had been beaten and crucified.
Fourth (and what should be most obvious), burial cloths as a rule DO NOT SURVIVE THE GRAVE. This one is unique in all the world simply by virtue of its existence.
I could go on and on, but there are many good sources of information which detail all of the scientific evidence for the authenticity of the Shroud. The Shroud of Turin website is a good place to start.