It doesn’t matter if you use your phone for calls, put it in your pocket or keep it on your bedside table – there is no good evidence that mobile phones can cause cancer. Several studies have looked at this issue, particularly whether using a mobile phone increases the risk of brain cancer where the phone is held close to the head. The majority of them – including the largest ones – have found no link between mobile phone and cancer, for at least 10 years of use. It is also telling that brain cancer rates have stayed flat over the past decades in countries where mobile phone use has skyrocketed, including New Zealand, the US, the UK and Scandinavia. If mobile phones cause cancer, you would expect to see at least a small rise in these rates by now. There is also no good explanation for how mobile phones could cause cancer. They give off low-energy microwave radiation, but there is no good evidence that this could damage DNA or alter our cells in other ways that might lead to cancer. However, we cannot rule out the possibility of a risk. This is because mobile phones have changed a lot over the past few decades and we still do not know a lot about their long-term effects. For this reason, the World Health Organisation recently classified mobile phones as a “possible” cause of cancer. This means that the evidence for a risk is limited, and we cannot draw strong conclusions from it. Big studies are currently underway to tell us more.