The roughly two thousand people walking around with glass-encapsulated RFID chips in their bodies are probably suffering from some headaches this week. Not because of the chips themselves, but the recent news that they might pose a health risk.

Though the chips are approved for use in humans by the FDA, the AP revealed recently that a number of animal studies, conducted from 1996 to 2006, showed that the implants can induce malignant tumors. The FDA stands by its approval, and implant-maker VeriChip says its products are perfectly safe. But scientists who reviewed the research had mixed reactions.—Gregory Mone