Quite apart from the cancer risk
What happens if you dislocate or otherwise damage your knee in an accident or suffer from arthritis or osteoporosis which is common in the elderly? Presumably it wouldn't be too effective in those whose bones are still growing either, leaving an effective age range of maybe only 25-50?
When will folk realise that biometrics have their inherent problems - peoples bodies are not a constant - and just give up?


