Radio's affects on health is my guess. I've heard this at least. Radio tech can affect health but bluetooth is so low wattage I have very little concern about it. Even if there are negative health affects to cell phone and bluetooth usage most people are doing so many other things we know have more impact on health that I chuckle at this issue.

There's something interesting about humans. We tend to focus on what is out of our control and instead focus on things we can't control. I'm sure there is a name for this but its so weird. We know sugar is bad for our bodies yet most people consume insane amounts of it. Just reducing or eliminating this would make a massive impact on the health of most people. But no, lets focus on things we don't understand, which are in high dispute from both research and experts in the technologies.