The findings -- presented at the American Society of Reproductive Medicine conference in New Orleans -- were based on a study of 361 men attending the clinic for infertility tests. The men were divided into four groups -- one group with no cell phone usage; one group that used cell phones less than two hours a day; a group that used one for two to four hours a day; and a group with more than four hours a day of cell phone usage. The men who used their cell phones in excess of four hours showed a 30 percent drop in sperm motility and viability when compared to the men who did not use cell phones. Sperm count, quality, and shape were also reduced with each level of increased phone usage.
"There was a significant decrease in the most important measures of sperm health and that should definitely be reflected in a decrease in fertility, which is seen worldwide," said Dr. Ashok Agarwal. "People use mobile phones without thinking twice what the consequences might 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 be having a huge impact because mobiles are so much part of our lives."
Agarwal suggested the cell phones might be harming the DNA of the phone users, disrupting their testosterone-producing cells, or shrinking the tubules that create sperm. He noted that the small study did not prove that male fertility was affected by cell phone use, but showed that further investigation was warranted. Scientists who heard the results called for factors such as age, weight, smoking, stress and sedentary occupations to be considered.
"This is a good quality study, but I don't think it tackles the issue," said Alan Pacey, senior lecturer in andrology at Sheffield University, U.K. "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 it that testicular damage is supposed to occur? If you are holding it up to your head to speak a lot, it makes no sense it is having a direct 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 is 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," he said.
"Sperm is very temperature sensitive as shown by many studies, and a short-term rise in temperature could be responsible," said Alasdair Philips, director of the consumer pressure group Powerwatch. Philips also theorized that mobile phones may only heat the groin area when men are doing things like sending text messages while the cell phone is in their lap, and suggested holding the phone away from the body before sending text messages.
"Although this was a relatively small study, its findings raise cause for genuine concern among both men and women," said Mike Adams, a consumer health advocate. "To suspect that long-term exposure to cell phone radiation may damage the DNA of sperm seems reasonable. If this is true, it is highly likely that many other organs and tissues in the body are similarly affected. Mobile phone radiation could turn out to be a 'hidden poison' that's partially responsible for the accelerating rates of infertility in Western nations."