Salam. I actually do not know the answer to this one.
Each man & woman have different finger tips (prints) and DNA. Perhaps his jaws are also unique.
What other things are completely unique for each man and woman?

The trivia forums are for questions for which the questioner has the answers. This should be posted in Science category, under Biology. I shall move it there, along with any replies, shortly.

Retinas (back of the eye) are also unique. I believe irises are as well, but I'm not certain about that one.

The most popular form of biometrics employed today is of course the fingerprint, though the error rate for fingerprint identification is sometimes as high as 1 in 500. A retinal scan, on the other hand, boasts an error rate of 1 in 10,000,000. Its close cousin, the iris scan, is slightly less precise, maintaining an error rate of approximately 1 in 131,000.

Traditionally used to block physical gateways, such as those guarding the cores of power plants or military installations, the retinal scan has been employed in recent times to safeguard critical computers and their data. The retinal scan retails for as low as $220, making it affordable to anyone wanting to maintain high levels of security. Furthermore, it is probably the most accurate biometric available, far surpassing the fingerprint in both reliability and accuracy. WiseGeek.com -

Something to point out. Although we believe that these are unique (you obviously can't prove it without looking at every fingerprint, iris, or retina that ever existed), it is not just the uniqueness that matters. It took years and a lot of money (millions, at least) to sequence the human genome. While we could do it faster and cheaper now, it would still not be realistic to do it for identification purposes. So, we have to look at a few parts of it that have a lot of variation. This sort of DNA test does not give a unique result for each person, but there are few enough matches that it is useful. The same goes for fingerprints - rather than matching the fingerprint 100%, a few key parts are used. I assume it's the same way for retinas and irises.

Thank you all.