Parents should not give cell phones to children aged eight or under, the chairman of an official study into the safety of the phones said Tuesday.

Sir William Stewart, chairman of the National Radiological Protection Board (search), or NRPB, said there was a growing amount of research that showed using cell phones has health implications and it was therefore wise to adopt a "precautionary approach," particularly with children.

"I don't think we can put our hands on our hearts and say mobile phones are safe," he told a news conference to launch his report.

"When you come to giving mobile phones to a three to eight-year-old, that can't possibly be right."

A British company that recently launched a phone aimed at 4- to 8-year-olds said it was suspending sales until it has studied Stewart's report.

Stewart concluded that "there is no hard evidence at present that the health to the public, in general, is being affected adversely by the use of mobile phone technologies."

However, Stewart said he was "more concerned" about the implications for health than five years ago, when he last reviewed cell phone use.

He added that there is evidence to show that "emissions from mobile phone masts are a small percentage of the emissions that one gets from a mobile phone," but recommended that such masts — blamed by some parents for making their families ill — should not be sited near schools.

Mike Dolan, executive director of the Mobile Operators Association (search), noted that the weight of scientific evidence so far "does not suggest that mobile technologies operating within international health and safety guidelines cause illness.

"The operators have a very good track record of responding positively to advice from the NRPB and the government," he said.

The Department of Health said its advice to be cautious in allowing cell phones for those under 16 remains in force.

Stewart said studies showing the use of cell phones could affect health "have yet to be replicated and are of varying quality but we can't dismiss them out of hand."

"This is still a relatively new area and the divergent views show how more research is needed."

He advised users to be cause and use text messaging as much as possible.

Communic8 (search) said it was suspending sales of its MyMo phones (search), which were designed for children and store up to five numbers that can be easily dialed in an emergency.

"We launched the product specifically because we thought it could address security concerns of parents," said marketing director Adam Stephenson.

"We absolutely do not want to damage children's health."