Brain cancer has a latency in the population of 40 years.

You can do something really radical, which is turn your phone off and reclaim your private life.

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.

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.

We get dopamine in the brain when we like something a lot. Well, cellphones stimulate dopamine, too. So it really is the case that there are some people who are pretty addicted to these devices.

The whole idea of what is evidence for causation in epidemiology cannot be separated from tTindustry understood that if they could raise doubt about how you could conclude something caused cancer, that they put so much effort into getting so many receptive public health authorities to say, "Well, causation requires that these five things be met." So that is, in fact, nonsense.

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.