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Mobile phones have been
identified as a cause of reduced sperm production in men.
Microwaves emitted by the phones reduce
the number, mobility and quality of sperm by almost half in the heaviest
users, to the point where some men may become infertile, scientists
say.
This could have devastating consequences for fertility rates around
the world.
Almost a billion people around the world use mobile phones, and the
number is growing. Even a small effect on fertility could result in millions of men being rendered
childless.
Concern about the health effects of mobile
phones has been rising for 10 years, but very little hard evidence of the dangers has been presented.
Scientists from the Reproductive Research Centre at the Cleveland
Clinic Foundation in Ohio, tested the sperm of 364 men being investigated for infertility. They found that
the heaviest users of mobile phones - more than four hours a day - had the lowest
sperm counts at 50 million a millilitre and the least healthy sperm, judged by its mobility and the
proportion of abnormal sperm.
Sperm counts were highest - 86 million a millilitre - and the sperm
healthiest among those men who did not use mobile phones.
All men produce a high proportion of sperm that are abnormal, but in
the heaviest mobile users the "normal"
sperm fell to 18 per cent compared with 40 per cent in those who never used mobiles.
The study was carried out in Bombay, India, where mobile phones have
not yet penetrated all social groups. Professor Ashok Agarwal, director of the research centre, who led
the study, said: "On all four parameters - sperm count, mobility, viability and morphology - there were
significant differences between the groups.
"The greater the use of cell phones, the greater the decrease in
these parameters [sperm count, mobility, viability and morphology]. That was very
clear and very significant.
"People use mobile phones without thinking what the consequences
may be. It is like using a toothbrush - but mobiles could be having a devastating
effect on fertility. It still has to be proved, but it could have a huge impact because mobiles
are so much part of our lives."
Among the heaviest users in the study, with an average sperm count of
50 million a millilitre, some had individual sperm counts of less than 20 million a millilitre. This is
below the threshold set by the World Health Organisation which defines infertility, Professor Agarwal said.
The finding, presented to the American Society for Reproductive
Medicine meeting in New Orleans this week, will spark renewed concern about the safety of mobile phones which
have been blamed for a wide range of ill effects, from headaches to cancer.
But critics said the only men likely to be affected were those who
carried their phones in their pockets or on their laps, close to their testicles, while they made calls.
A report by Britain's National Radiological Protection Board
published last year concluded there was "no hard evidence" that mobile phones caused harm, but it was too
early to say if they were safe.
It said health problems could take decades to emerge and,
because of the ubiquity of mobile phones, a "precautionary approach" was necessary.
Children, whose bodies were still
developing, were most likely to be vulnerable, it said.
Another study last year by Professor John Aitken, a British
researcher at the University of Newcastle in New South Wales, showed radio waves of a
similar frequency to those emitted by mobile phones damaged sperm DNA in mice.
Other studies have shown the seminiferous tubules, where sperm is
produced in the testes, shrink when exposed to the speech transmission mode of mobile
phones.
Professor Agarwal said phone could be causing direct damage to the
Leydig cells in the testes, which have been shown to be susceptible to microwaves, or could be setting
up a heating effect or damaging the sperm DNA.
Among scientists sceptical of the study findings is Allan Pacey,
senior lecturer in andrology at the University of Sheffield. "This is a good-quality study but I
don't think it tackles the issue," he said. "If you're using your phone for four hours a day,
presumably it is out of your pocket for longer. "That raises a big question - how is testicular
damage supposed to occur? If you are holding it to your head to speak, it makes no sense that it is having
an effect on your testes. "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."
But Alasdair Philips, director of the British consumer pressure group
Powerwatch, said: "It's a plausible link between the amount of time spent using a mobile phone and
a possible effect on male fertility.
The eyes, breasts and testicles are the
areas of the body most likely to absorb the energy, and many men attach their mobiles to their
belt."
"I've seen men on trains spending two or three hours texting
with their mobile phones held in their laps. They press 'send' in the same position, and the phone starts
to seek a signal. This needs a considerable amount of power within what is effectively a metal
box.
"We advise people to send texts with their arm outstretched next
to the window when travelling on a train."
He said local heating of the groin triggered by a mobile phone
might also affect sperm quality. "Sperm is temperature-sensitive, and a short-term rise in
temperature could be responsible."
- INDEPENDENT |
