Do mobile phones 'cook' sperm?

Certain aspects of mobile phone usage may be linked to abnormal sperm concentration, according to research.

The study, reported in the journal Reproductive BioMedicine Online, found an association between talking on a mobile for at least one hour per day, or using a mobile phone while it is charging, and higher abnormal sperm concentration.

'We analysed the amount of active swimming sperm and the quality and found that it had been reduced. We think this is being caused by a heating of the sperm from the phone and by electromagnetic activity,' said study author Professor Martha Dirnfeld, from the Technion University in Haifa.

This was a small study based on questionnaires from 80 men who had been referred for semen analysis at an IVF clinic in Israel.

Most of the men had normal semen volume, sperm morphology and motility. Overall, 57 percent had normal sperm concentration. But 61 percent of men with abnormal sperm concentration reported speaking on the phone for more than an hour a day, compared with only 39 percent of those with normal sperm concentration.

And, two-thirds of men with an abnormal concentration said they used their device while it was charging compared with only a third of those with normal concentration.

However, other indicators of fertility were not associated with mobile phone use in the study. There was also no relationship between where men usually kept their phone when it was not in use and abnormal sperm concentration.

The small sample size and the fact that all of the participants were already experiencing fertility problems may make it difficult to draw any firm conclusions about the effects of mobile phones on fertility. In addition, the association shown in this study is with abnormal sperm concentration and not with infertility itself.

'There is not yet any direct evidence available to link mobile phone use with complete infertility,' Dr Fiona Mathews, from the University of Exeter told the Telegraph. 'All we can say at the moment is that mobile phone exposure reduces sperm quality and it would therefore be reasonable to infer that, for men who are already on the borderline of infertility, phone exposure could further reduce the chances of pregnancy.'

Professor Allan Pacey, from the University of Sheffield said that most studies looking at the link between sperm quality and mobile phone use have been badly designed. '[They] either simply irradiate ejaculated sperm with mobile phone radiation in a dish – which is not physiological – or only look at semen quality in men who do or don't keep a mobile phone in their pocket – without accounting for any other variables. As such, I remain unconvinced.'

He added: 'I think we probably need a large multi-centre study to sort this out once and for all.'