Government scientists have called for a fresh investigation into any possible links between electromagnetic radiation and some cancers.
Denise and Ray Studholme lost their son Simon after moving home
BBC News Online talks to one family who believes their son died as a result of sleeping too close to electric appliances.
In January 1989 Ray and Denise Studholme moved into their dream bungalow in Little Lever, Bolton.
Less than four years later their 13-year-old son Simon died after a long fight with leukaemia.
His father Ray recalls how within about six months of the family moving in, Simon began complaining of pains in the head.
"He said it was like someone forcing his head down, like pressure in the head."
By November the following year he had been diagnosed with lymphoblastic leukaemia and set on a course of chemotherapy.
This was a death sentence for someone of his age - as the survival rates for older children from this disease are very low.
But after several months, he seemed to be rallying, and even went back to school, Mr Studholme remembers.
Sadly, however, by May 1992 he had relapsed.
"From then on he went through hell. He was in agony, We could see him dying in front of us," Mr Studholme said.
He remembers mentioning to the consultant that they lived near a sub-station and several pylons - but the doctor was dismissive and urged him to concentrate on getting Simon better.
After Simon's death on 19 September 1992 the family began to question whether electromagnetic fields caused by the substation could have impacted on Simon's health.
They had tests done in Simon's bedroom and found very high electromagnetic readings - not emanating from the pylons outside - but from a burglar alarm and an electricity meter next to the child's bed.
Electromagnetic readings in Simon's bedroom were found to be very high
"To this day, my wife and I are positive that this contributed to Simon's leukaemia," Mr Studholme said.
They feel there should have been warnings on the appliances saying that there could be a risk from the electromagnetic fields they created.
The Studholmes tried to take their electricity supplier to court, but were told the case would fail.
Now the family take extra precautions.
They have got rid of the burglar alarm and none of their other children sleep in Simon's old room.
They also ensure that they turn the electricity off at the mains - every single night.
"We have done what we can - we went as far as we could. If there was anything I could do or give up to bring Simon back then I would do it.
"But that's not going to happen," Mr Studholme added.