Can cell phones make you sterile?

A Cleveland Clinic study found that cell phone use may contribute to fertility problems in men.  See more cell phone pictures.
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Ashok Agarwal, Director of the Center for Reproductive Medicine at the Cleveland Clinic, uncovered a potentially unhealthy relationship between men and their cell phones in 2008. Agarwal and his colleagues recruited 361 men and compared the health of their sperm with their cell phone activity. Dividing participants into groups based on self-reported cell phone use, researchers found a positive correlation between lackluster sperm and greater talk time. Not only were men in the high-use group spending more than four hours per day on their cell phones, they all had lower sperm counts relative to the other three groups [source: Agarwal et al].

Given the correlation between cell phones and diminished male fertility, why aren't we hearing about the resurgence of the rotary? While Agarwal's results were compelling, too many controls were unaccounted for, such as inaccuracy of self-reporting and lifestyle factors that could also contribute to low sperm count. But Agarwal isn't the first medical researcher to question the health effects of frequent cell phone use. Some think the electromagnetic radiation the phones emit warrants closer scrutiny.

Whenever we talk into a cell phone, an internal transmitter converts our voices into continuous sine curve waves that the antenna then dispatches in the form of radio frequency energy. This form of traveling energy, called radiation, is the same stuff that enables other telecommunications devices, including televisions, radios and cordless phones [source: Federal Communications Commission]. And since cell phone radiation is classified as non-ionizing, meaning that it isn't powerful enough to destroy atoms and molecules by stealing electrons, it isn't considered acutely harmful to humans.

Although non-ionizing radiation doesn't pose an immediate danger (unlike that of gamma rays and X-rays), our bodies still absorb some of it whenever we chat on our cell phones. The Federal Communications Commission (FCC) established the Specific Absorption Rate (SAR) as the legal amount of electromagnetic radiation that cell phones can release without posing a health threat to humans. The SAR in the United States is 1.6 watts per kilogram, and it's 2 watts per kilogram in Europe. Though federal regulators intend SAR as a safety precaution, the ubiquity of cell phones and their constant proximity to the body have raised red flags about whether those radiofrequency waves are truly benign -- or whether they can harm sperm after all.


Hang-ups About Cell Phone Radiation

Cell phone radiation may affect human cell behavior.
Cell phone radiation may affect human cell behavior.
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A few months after the Cleveland Clinic published its initial study on cell phone use and sperm, lead researcher Ashok Agarwal followed it up with a related experiment. He took 32 sperm samples -- 23 from healthy men and nine from men with existing infertility problems -- and divided them into a test group and a control group. Samples from both groups were stored in identical environmental conditions, except that the test group sat 0.98 inches (2.5 centimeters) away from a cell phone in talk mode. After just an hour of radiation exposure, the test group exhibited a 7 percent decrease in sperm motility and an 11 percent drop in the number of living sperm [source: Raymond]. Moreover, that same test group showed an 85 percent jump in the production of unstable atoms called free radicals.

Agarwal's sample size is too small to draw definitive conclusions, but he suspects that the thermal effect of cell phone radiation may have caused the negative sperm reaction. Muscle, tissue and fat help insulate the body from the thermal effect, but the eyes and the testes are more generally exposed and susceptible due to relatively low blood flow to those areas [source: Krewski et al]. And while the legal cell phone radiation limit (SAR) set by the Federal Communications Commission (FCC) is considered well below the thermal effect threshold, researchers at the Finnish Radiation and Nuclear Safety Authority found that the radiofrequency waves can nevertheless impact human cell behavior. In their study, researchers noted that exposure to the non-ionizing waves affected the expression of two types of proteins [source: New Scientist].

Over the past decade, cell phones have come under additional scrutiny, with researchers linking them to higher incidence rates of cancers, brain tumors, sleep disturbances and other disorders. But the U.S. Food and Drug Administration (FDA), which partners with the FCC to monitor cell phone radiation, maintains that mobile devices are safe. In addressing the issue of cell phones and health problems, the FDA contends that studies have merely established a correlation instead of a verifiable causation.

The $30 million Interphone study on the health effects of cell phones aptly illustrates how the correlation-causation debate has muddied the waters. Fifty scientists in 13 countries examined the frequency of cell phone use and the health conditions of 14,000 participants [source: The Economist]. After six years, the results were about as fuzzy as old-school analog reception.

Crossed Lines: Studying the Health Effects of Cell Phones

The FDA considers cell phones safe to use.
The FDA considers cell phones safe to use.
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The Interphone study asserted that long-term cell phone use increases the incidence rate of certain brain tumors in the auditory region. But the same body of research also claimed that long-term use protects a person against developing other kinds of brain tumors. Because of such contradictory conclusions, researchers have headed back to the drawing board to refine the study parameters.

Another major hurdle for verifying whether cell phones pose danger is that they simply haven't been around that long. It takes anywhere from 10 to 20 years for brain tumors to develop, and a lot of people haven't owned a cell phone for that long [source: Butler]. Also, researchers have yet to accurately delineate between heavy and casual cell phone users. In comparing actual phone records against self-reported cell phone habits, the Interphone scientists found that participants underestimated the number of calls made and overestimated the duration of individual calls [source: The Economist]. Without more accurate data, study results can't be fully trusted.

With many questions left to be answered, the FDA has given cell phones a cautionary stamp of approval. The agency states that research hasn't proven any adverse health effects but also notes that it can't rule out the possibility that they may come to light in the future.

Cell phone sales indicate that the public isn't terribly concerned, either. A 2008 survey from the Centers for Disease Control and Prevention (CDC) showed that more than one in six American homes has opted for wireless over landlines [source: Blumberg and Luke].

As for Ashok Agarwal at the Cleveland Clinic, his studies on cell phones and sperm have only begun. In the meantime, if men are worried that Agarwal will prove his theory right, they don't have to ditch their mobiles. Rather, Agarwal encourages men to remove phones from their pockets while talking into mobile headsets. Speaking of headsets, experts recommend them as a way to reduce cell phone radiation exposure in general since callers don't have to hold a phone against their faces [source: Parker-Pope]. In addition, keep conversations short when reception is low, since the phone has to work harder to snag a signal.

And finally, don't believe every headline that touts the indisputable safety or danger of cell phones. It's probably going to be a while before scientists eliminate all of static obscuring the health debate over cell phones.

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  • Agarwol, Ashok et al. "Effect of cell phone usage on on semen analysis in men attending infertility clinic: an observational study." Fertility and Sterility. January 2008. (July 28, 2009)
  • Blumberg, Stephen J. and Luke, Julian V. "Wireless substitution: Early release of estimates from the National Health Interview Survey, January-June 2008." National Center for Health Statistics. Dec. 17, 2008. (July 28, 2009)
  • Butler, Kiera. "The Is Your Brain on Cell Phones." Mother Jones. July/August 2008. (July 28, 2009)
  • The Economist. "Mobile Madness." Sept. 25, 2008. (July 28, 2009)
  • Federal Communications Commission. "Radio Frequency Safety." Updated Dec. 11, 2008. (July 28, 2009)
  • Food and Drug Administration. "Do cell phones pose a health hazard?" U.S. Department of Health and Human Services. Updated June 30, 2009. (July 28, 2009)
  • Gajilan, Chris. "Cell phones can affect sperm quality, researcher says." CNN. Dec. 9, 2008. (July 28, 2009)
  • Krewski, Daniel et al. "Recent Advances in Research on Radiofrequency Fields and Health: 2001 - 2003." Journal of Toxicology and Environmental Health, Part B. Vol. 10. 2007.
  • New Scientist. "Cellphone radiation affects cells in living humans." Feb. 23, 2008. (July 28, 2009)
  • Parker-Pope, Tara. "Experts Revive Debate Over Cell Phones and Cancer." New York Times. June 3, 2008. (July 28, 2009)
  • Raymond, Joan. "Is That a Phone in Your Pocket?" Newsweek. Sept. 18, 2008. (July 28, 2009)