Just in case you don’t know. Bluetooth emits enough amount of radiation could harm you. However a cell phone to your head would be at greater risk than a bluetooth or wireless headset. So maybe speaker phone is best? oh wait how about just texting is much better, no need to bring the phone to your head. Well, in that case, why not just use the speaker phone? crap! just go back using wired headset, better quality, but a little bit of a inconvenient having that wire wrap around you.
Anyhow, I just want to point out that bluetooth does emits some level of radiation, whether it will harm greatly or not is still depend. But, definitely it is less risk than having that cell phone or smart phone whatever to your head. Here is a good research done by someone. http://www.electricsense.com/1010/bluetooth-what-you-will-learn-nowhere-else-%E2%80%93-is-it-really-dangerous/