"The Bluetooth devices, which many people are using these days because of health or safety concerns, may not be always so safe. There is a downside," he says.

Men who use these hands-free devices tend to carry their cell phones in their pants pocket or clipped to their belts at the waist while in talk mode. As a result, they may be exposing their testicles to damaging radiofrequency electromagnetic waves, explains Ashok Agarwal, PhD, head of the andrology laboratory and the director of the Center for Reproductive Medicine at the Glickman Urologoical and Kidney Institute at the Cleveland Clinic in Ohio.

Sept. 19, 2008 -- Men, beware: Using a hands-free device with a cell phone may affect your fertility if you keep your phone close to your testicles, Cleveland Clinic researchers warn in the journal Fertility and Sterility .

Cell Phone Radiation Affects Sperm Quality

To arrive at their findings, researchers collected semen samples from 32 men and divided each man's sample into two parts. They placed half of the semen samples 2.5 centimeters away from a 850 MHz frequency cell phone in talk mode for one hour. Most cell phones used in the U.S. are 850-900 MHz. They chose this distance because it is the typical distance between the testes and the trouser pockets.

Previous research from the same group showed that radiofrequency electromagnetic waves emitted from cell phones can impair sperm quality, and the new study shows why this may occur. Semen exposed to radiofrequency electromagnetic waves emitted from cell phones had higher levels of damaging free radicals, lower sperm motility (the ability of the sperm to move and swim) and sperm viability (the percentage of live sperm), and possibly greater oxidative stress, the study shows. There were no significant differences in DNA damage between the exposed and unexposed groups.

"Our findings appear to be in line with other concerns that environmental factors such as toxins, pollutants, and materials used in farming play a role in male infertility," Agarwal says.

Further study is needed to validate the findings. "We will also test the effect [of radiofrequency electromagnetic waves emitted from cell phones] at other distances," he says. "We know the radiation impairs sperm quality at 2.5 centimeters, but we don't know if the effect will continue at 3, 4, or 5 centimeters," he says.

Future studies will determine if there is dangerous emission when the phone is in silent or standby mode.

"The emission may be smaller than when in talk mode, but could it still be harmful if it reaches the testes," he says.