The problem

If you have a child of 10 years old or more, chances are they'll have a mobile phone. Maybe you gave it to them to keep safe, so you would know where they are, but mobile phones are not without their own risks. Not only can your children waste an enormous amount of time texting their friends instead of doing their homework, but mobile phones emit radiofrequency energy – a form of non-ionising electromagnetic radiation that is absorbed by the brain. Last month the World Health Organisation said that mobile phones could "possibly" be carcinogenic, putting them in category 2b (with other substances that "possibly" cause cancer such as car exhaust fumes, lead and coffee). Children, who will not have finished developing and therefore have thinner skulls, could absorb more of this radiofrequency energy than adults and be at a greater risk of developing brain tumours. This radiation is non-ionising radiation, which unlike ionising radiation from radon and x-rays has not consistently been linked to causing cancer.

The dilemma

Should you rip your child's BlackBerry from his or her hands, mid instant-message session? Or if the evidence is inconclusive and the WHO says it's only likely to cause as much harm as coffee, maybe mobile phones are relatively safe.

The WHO spent a week reviewing the evidence from 14 countries. Very little research exists on the effects of mobile phones on children. The largest study, the Interphone study found no evidence that mobile use increased the risk for gliomas and meningiomas (types of brain tumours). However a small proportion of people in the study who spent the most time on mobile phones did have a small increase in gliomas, reporting them to be on the same side of their head as they used their phones. However this could have been due to reporting bias, ie people may have mistakenly remembered which side of the head they held their phone against. It may take decades for a brain tumour to develop, so memories of phone use from way back can be unreliable, and studies may not have long enough follow-up periods to detect when brain tumours develop.

A study by the Swiss Tropical and Public Health Institute of children aged between seven and 19 found no difference in brain tumours in those using mobile phones and those without. The study looked at more than 350 people with brain tumours and tracked their mobile phone use. It was funded in part by mobile phone manufacturers, and critics have cited this as a potential for bias, as well as the fact that tumours can take many years longer than the time period of the study to develop. So far the incidence of brain tumours has not increased during this time of proliferation of mobile phones.

The solution

There is no evidence that mobile phones cause brain tumours, but that doesn't mean there might not be, one day. Given that using mobile phones excessively can cause problems for your child – sleeping, doing their homework and being a social human being in the house – it makes sense to try to limit their use.

To reduce your child's exposure to radiofrequency energy get them to text rather than phone (which they're probably doing already) and to use hands-free so the phone is not pressed against their ears.

The latest advice from the chief medical officer in the UK was that children under the age of 16 should keep calls short and use their mobiles only for "essential purposes". More evidence on the effects of mobile phones is being gathered. Cosmos, a large international study of mobiles and long-term health effects has been launched, which will enrol about 250,000 mobile users (they will be 18 and over) and track them for 20 to 30 years. An international study looking at children called Mobi-Kids has also kicked off in Spain. So at least you'll know what to do about your grandchildren.