By Stuart Corner    
 
A study of men with low sperm counts has found some correlation with heavy cellphone usage, but no convincing causal relationship has been put forward and sceptics suggest other lifestyle factors likely to be found in heavy cellphone users could be to blame.

361 men visiting a fertility clinic had their sperm analysed prior to starting treatment and were asked about their cellphone usage patterns. They were divided into four groups, with 40 never using a mobile, 107 using one for less than two hours a day, 100 for two to four hours daily and 114 for four or more hours a day.

The main finding was that on four measures of sperm potency - count, motility, viability and morphology, or appearance - there were significant differences between the groups, and the greater the use of mobile phones, the greater the reduction in each measure.

Professor Ashok Agarwal, director of the Reproductive Research Centre at the Cleveland Clinic, Ohio, who led the study and who presented the results at the American Society for Reproductive Medicine annual meeting in New Orleans, said: "This was very clear and very significant. Many in the lowest group for sperm count would be below normal as defined by the World Health Organisation...There was a significant decrease in the most important measures of sperm health with cellphone use and that [decrease] should definitely be reflected in a decrease in fertility."

Agarwal was reported suggesting that the damage could be caused directly by electromagnetic radiation from the phone or from the heating effect of the phone's radiation. He suggested that men's habit of carrying a phone on their belt could place it in sufficient close proximity to their testicles (however phones on belts are not in use so transmit only very intermittently) and also the habit of some men of sitting with their phones on their lap sending many text messages.

Sceptics however suggested the correlation between sperm count/damage and high mobile phone usage was more likely to be due to other behaviours likely to be exhibited by heavy phone users, and known to be detrimental to sperm quantity and quality.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, was reported saying: "Maybe people who use a phone for four hours a day spend more time sitting in cars, which could mean there's a heat issue. It could be they are more stressed, or more sedentary and sit about eating junk food getting fat. Those seem to be better explanations than a phone causing the damage at such a great distance."