I don't want to restart anything which has already been debated here before, unless I think you have got your facts wrong. An opinion is an opinion, and while it should be open to changing, it cannot necessarily be refuted by facts. I am very familiar with the Shroud, and all the evidence, circumstantial or not, for authenticity and for a medieval origin, and the idea that a medieval origin has "almost no evidence to support it" is laughable. A list might include the following:
1) The radiocarbon dating of 1988, which clearly dated a piece of the cloth to about 1350.
2) The unnatural dribbling of the bloodflows.
3) The neat and well defined scourge 'welts'.
4) The weave of the cloth.
5) The denial of authenticity by Bishop d'Arcis.
6) The denial of authenticity by Pope Clement VII.
7) The fact that the feet, rather than the head, are at the ends of the cloth.
The long, narrow shape of the cloth.
9) The extensive use of 'shrouds' throughout medieval Europe as part of the 'Quem Quaeritis' Easter ritual.
10) The quantity of red ochre.
11) The absence of any mention of a double imaged relic of Christ before the Shroud's appearance at Lirey.
Now before bippy sharpens his quill for the comeback, let me say that none of these is necessarily conclusive. It is possible for somebody to attempt to claim that there isn't enough red ochre, or that Bishop d'Arcis was lying, or that a Roman scourging really would leave neat and well defined welts, but my point is that these are opinions, not facts. I would never claim that the Shroud is indisputably medieval, merely that in my opinion, the weight of evidence tends towards that conclusion. If bippy, or anyone else, thinks they have conclusive evidence in favour of authenticity, I'd love to read it; but I certainly wouldn't claim that any of my evidence was conclusive.
While composing this, I've just seen the new post above. For those not familiar with the issue, it is sometimes claimed that the area tested by the radiocarbon labs was a mixture of 1st century threads and some much later addition, say 16th or 17th century, and together the mixture resulted in the fortuitous date of 1350, which coincidentally matches the date of the first confirmed appearance of the shroud at Lirey in France. It is a matter of simple mathematics to show that the interpolated material would have to be twice the mass of the original material to achieve this date. Various studies have suggested that there may be a smear of pigment over the area, and some have claimed to find cotton fibres in various proportions, but no-one has recently defended the two-thirds-modern one-third-ancient composition, since Marino and Benford's original proposition (that the radiocarbon sample area was neatly divided lengthways into two strips, one ancient, one modern) was shown to be untenable.
The 'obvious' linkage between the Sudarium of Oviedo and the Shroud of Turin is not as obvious to me as it is to authenticists. Although both artifacts have been well known for centuries, the 'obvious' linkage was not made until a few years ago, when various scientific tests may - or may not - have been performed on the Sudarium. It is said to have been carbondated twice, with neither date anywhere near the 1st century; it is said that it is largely covered in pleurocardial serum; it is said to have the same pollen assemblage as the Shroud; and it is said that marks on the Sudarium correspond with marks on the Shroud to an extraordinary degree. There is no published evidence for any of these statements. Various reputable authors of impeccable integrity believe them, and refer to them, but I have never seen any evidence to substantiate their belief, in spite of continuous inquiry.
It is popularly supposed that the 'wrist wound' on the Shroud clearly demonstrates that the nail is not in the palm of the hand, as shown in most medieval crucifixions. Few people have even noticed that the medieval crucifixions show the hands from the front, while the Shroud shows the hands (one hand) from the back. Fortunately the knuckles are quite well defined, and measurement of the length of the fingerbones, relative to the distance of the nail-hole from the knuckles, brings the site of the exit wound far further forward than the wrist bones. Arguments that nails through the palms would tear out are completely negated by the fact that most early crucifixes show Jesus standing on a platform, so he wasn't actually hanging from the nails at all.
Let me reiterate that I don't want to proselytise for a medieval origin here, but I would like simply to make it clear that the authenticity of the Shroud is far more debatable than bippy suggests.
Footnote: while previewing this comment, I see that the number 8 above has been replace by a grinning alien. Weird.