The VeriChip has been FDA-approved for human implantation but civil liberties advocates are worried.

The VeriChip, a small radio-frequency identity chip that is slightly longer than a grain of rice, has been FDA-cleared for human implantation. Should you switch doctors or need to be treated in a foreign hospital, an RFID reader can scan your VeriMed chip and use your unique ID to access VeriChip's centralized database to produce your medical records. The chips themselves do not necessarily represent a threat to your privacy, because they don't store the data. But the centralized databases certainly do.Much more frightening, say civil liberties advocates, is the possibility that the VeriChip could be employed as a tracking device-though the manufacturer claims the chip cannot be read unless a sensor is held right next to it. In any case, Americans appear to prefer convenience to privacy: drivers of major freeways continue to sign up for the RFID-based toll device E-ZPass, even though the company has shared its vehicle tracking information with the FBI.