At the moment nobody is sure of the impact of mobile phones on our health because people haven't been using them long enough - but early signs are worrying.
A UK health research group has discovered an increase of brain and acoustic neuroma (ear) cancers, and the figures are almost "statistically significant", which means the figures are nearly high enough to suggest a definite link.
The group, the UK Mobile Telecommunications and Health Research Programme (MTHRP), said it was vital to carry out more research, otherwise people were in danger of falling into the same trap when cigarettes were not initially linked to lung cancer.
Programme chairman Prof Lawrie Challis comments: "We can't rule out the possibility at this stage that cancer could appear in a few years' time. With smoking there was no link of any lung cancer until after 10 years."
Cancers usually do not appear until 10 to 15 years after exposure.
Aside from the longterm concerns, Prof Challis said that mobile phones do not appear to have an immediate impact on health.
(Source: MTHRP website).