The reality is, the way we've used phones and the amount that we've used phones has changed radically in the past five years. When phones were first marketed in the 1990s, it cost, for car phones, $3000 to buy a phone and the average person did not use it that much. They were very, very expensive.

The younger a cell, the faster it grows, the more vulnerable it is to damage.

Cellphone and other wireless radiation should be classified as a "probable human carcinogen."

There's an increase in serious weight disorders from cellphone use. And people who don't sleep have serious other consequences for their health that can be associated with it. There may be as well increases in problems with their memory. And all of those things are not as sexy and don't demand as much attention as cancer, but they can be very, very important from a public health point of view.

When the signal is weak, the phone is working more, you drain the battery faster, so only use a phone when the signal is weak in a true emergency.

We know that drugs, sex and rock and roll stimulates something called dopamine in the brain. So do videogames. Dopamine is something that we crave.

In particular, recently Belgium has banned the sale of a cellphone to a 7-year-old. Turkey has banned ads and advertising to children. So has France for children under 12. India has bans in certain areas. In Bangalore, you cannot sell a cellphone to someone younger than 16. So in different parts of the world, they've taken different steps.