docinthemachine writes "Cutting edge military R&D from DARPA has developed a way to smell out bad guys- literally. Move over fingerprints and biometrics- this is what I call "smellcheck". Darpa's "Unique Signature Detection Project (formerly known as the Odortype Detection program)" aims to sniff out genetic markers in "human emanations (urine, sweat, etc.)" that "can be used to identify and distinguish specific high-level-of-interest individuals within groups of enemy troops." There is real science behind this. Specific molecules excreted in urine were related to MHC molecules. The MHC (major histocompatibility complex) antigens are molecules on the surface of cells that the body uses to recognize self vs non-self. The MHC genes are the genes that code for these molecules. Whena person is "matched" for an organ or bone marrow transplant these are the factors that are being matched. Therefore- this new military technology being used to sniff out terrorists in a group could be used to rapidly and noninvasively screen large groups of people for potential transplant matches. This medical concept has already been tested in mice and appears to work. Just get ready to have your arm pits sniffed at the border to see if you are a suspected terrorist. That's another bad job for the list. You can read further details at docinthemachine.com at http://docinthemachine.com/2007/01/05/smellcheck/"