Updated

Men who carry their cell phone or Blackberry on their belt loop or in their pocket may be posing a risk to the health of their sperm and their fertility.

A major health advocacy group released a new report on the potentially harmful effects of cell phones on sperm. The Environmental Working Group (EWG) reviewed the scientific literature and reported that 10 studies have found significant changes in sperm exposed to cell phone radiation.

The study reported: “In the most striking findings, men who carried their phones in a pocket or on the belt were more likely to have lower sperm counts and/or more inactive or less mobile sperm.”

“People are so preoccupied with brain tumors that the fertility issue gets very little play,” said Louis Slesin, editor of Microwave News, a newsletter on electromagnetic radiation.

Exposure to cell phone radiation has also been associated with markers for sperm damage, such as higher levels of reactive oxygen species (chemically reactive molecules containing oxygen), oxidative stress, DNA damage and changes in sperm morphology.

“We have enough evidence to issue precautionary health warnings,” said Dr. Joel Moskowitz, director of the Center for Family and Community Health in the School of Public Health at the University of California at Berkeley. “The evidence for sperm damage is quite consistent across many studies,” he added.

“The issue is far from settled, yet the proposals put forward by EWG are low-cost precautionary actions,” Slesin said.

Another review article published last year in the Journal of Andrology examined the scientific literature on both animals and humans. Those authors came to similar conclusions as the EWG report. But they also cautioned that “more studies are necessary to provide stronger evidence that cellular phone use disturbs sperm and testicular function because the existing literature has several limitations.”

The EWG highlighted several results from the existing studies:

Men who carried a phone in a hip pocket or on the belt had 11 percent fewer mobile sperm than men who kept a phone elsewhere on the body.

Men who carried a cell phone on the belt and used it intensively during a five-day test period had a 19 percent drop in highly motile sperm from their previous levels.

Men who talked on the phone for more than an hour a day had 17 percent fewer highly motile sperm than men who talked less than 15 minutes a day.

Using a Bluetooth device or other headset may actually make things worse because you’re likely to keep your device on your belt or in your pocket while using the phone. This means that although the head is not exposed to radiation when the phone is in use, the sperm are being constantly exposed.  According to the EWG report, several studies have found lower sperm count and poorer sperm quality in men who use Bluetooth devices or headsets compared to men who put their phones to their ears.

“Men just need to take simple precautions to reduce potential harm from cell phone use,” Moskowitz said.  According to EWG:

• Men can carry their cell phones in their pockets if they keep them turned off, and turn the phone on periodically to check for messages.

• Men should always remove their cell phone from their pockets when making a call using a Bluetooth or headset as most electromagnetic radiation is emitted from the phone when talking on the phone.

Check this list for the cell phones that emit the highest radiation.