I think if someone is worried about the level of radiation from any device, just dont use it. But such discussions are out of place here. Everything in life is a balance of risks and benefits. Be an adult, make up your own mind, and move on. The studies to date are very difficult to interpret. I dont think they will ever yield a clear-cut answer. Just anecdotally, the neurosurgeons I used to work with all used a Bluetooth headset. None of them would hold a cell phone to their ear. Thats not data, just their bias.