What do you think of hands-free kits while driving?

This seems obvious: when drivers have both hands on the wheel, they run less risk of having an accident. That is why more and more countries prohibit the use of portable hand at the wheel, Bluetooth headset or hands-free kit is most often tolerated or permitted.
However, some studies suggest that call with a headset would be as dangerous as driving drunk. And even if the subject is controversial, it is reasonable to assume that one is necessarily distracted in his conduct when phone while driving. So, in your opinion, should be purely and simply prohibit the phone while driving?
Tags: ads, cellular phones, Peripherals, Polls, smartphones, Wireless