Men who use mobile phones could be risking their fertility, warn researchers.
A new study shows a worrying link between poor sperm and the number of hours a day that a man uses his mobile phone.
Those who made calls on a mobile phone for more than four hours a day had the worst sperm counts and the poorest quality sperm, according to results released yest at the American Society for Reproductive Medicine annual meeting in New Orleans.
Doctors believe the damage could be caused by the electromagnetic radiation emitted by handsets or the heat they generate.
The findings suggest millions of men may encounter difficulties in fathering a child due to the widespread use of mobile phones and offers another possible explanation for plummeting fertility levels among British males.
Sperm counts among British men have fallen by 29 per cent over the past decade, a drop which has also been blamed on increasing obesity, smoking, stress, pollution and 'gender-bending' chemicals which disrupt the hormone system.
The latest study backs up previous research which indicated a link between mobile phone use and sperm quality, but it is the biggest and best designed to date.
US researchers in Cleveland and New Orleans, and doctors in Mumbai, India, looked at more than 360 men undergoing checks at a fertility clinic who were classified into three groups according to their sperm count.
Men who used a mobile for more than four hours a day had a 25 per cent lower sperm count than men who never used a mobile.
The men with highest usage also had greater problems with sperm quality, with the swimming ability of sperm - a crucial factor in conception - down by a third.
They had a 50 per cent drop in the number of properly formed sperm, with just one-fifth looking normal under a microscope.
Professor Ashok Agarwal, director of the Reproductive Research Centre at the Cleveland Clinic, Ohio, who led the study, said "Almost a billion people are using cell phones around the world and the number is growing in many countries at 20 to 30 per cent a year.
"In another five years the number is going to double. People use mobile phones without thinking twice what the consequences may be.
"It is just 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."
Phone the doctor: Men who use mobile phones could face increased risk of infertility
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