Recitation Section 1 Answer Key February 8-9, 2006 Biology as a Science Please read the following article. Class discussion will focus on the article, and center around the questions that follow. Mobile Phones Can Cut A Man's Fertility By A Third RESEARCH into the fertility of men who regularly carry and use mobile phones has suggested their sperm count can be cut by up to 30%, reducing chances of conception. Jonathan Leake, Science Editor The 'Sunday Times', June 27, 2004: The study is the first to indicate male fertility may be damaged by the radiation emitted by mobiles. Men who carry the phone in a belt holster or trouser pocket are thought to be at the highest risk and could one day be advised to put the mobile in a bag or briefcase and away from vulnerable areas. Details of the research will be released on Tuesday at an international scientific conference of fertility experts in Berlin. The researchers studied 221 men for 13 months comparing the sperm of those who used their phones heavily with others who did not. They found that heavy users of mobile phones, those who carried their phone around with them most of the time, had their sperm counts reduced by nearly 30%. Many of the sperm that did survive showed abnormal movements further reducing fertility. While the research suggests an effect on the sperm, the scientists say further work will need to be done to confirm the finding and establish the mechanism by which it might happen. In the paper, Dr Imre Fejes of the obstetrics and gynaecology department at the University of Szeged in Hungary concludes: "The prolonged use of cell phones may have a negative effect on spermatogenesis (sperm production) and male fertility, that deteriorates both concentration and motility." Unlike previous studies, the researchers believe that phones may cause damage while in stand-by mode. Although not in use, they make regular transmissions to maintain contact with the nearest radio masts. It had been assumed such transmissions were too short to cause harm. In the study, the researchers looked at men using mobile phones operating on a single frequency. In Britain the picture is more complex with a range of technologies and frequencies in use. Experts believe, however, that if biological or health effects were to emerge, they would probably be found across the spectrum. Lawrence Challis, emeritus professor of physics at Nottingham University, who chairs the government's Mobile Telecommunications and Health Research Group, said that although there were many studies into the health effects of mobile phones, the results were too contradictory to draw firm conclusions. "There is no conclusive evidence of damage to health, but mobile phones have only been around for about 15 years," he said. "Many serious diseases take much longer than that to produce symptoms and there is no way the research could show this up." Later this year Challis will announce plans for the world's biggest study into the health impact of mobile phones. He wants to follow the lives of 250,000 people for at least 15 years - simultaneously tracking their phone usage from data supplied by mobile phone companies. Challis also sits on the Advisory Group on Non-ionising Radiation. In a report last January it reviewed the evidence for damage to sperm by mobile phone radiation, but concluded that although there was a theoretical risk there was too little research to draw conclusions. A spokesperson for the Mobile Operators Association, which represents the five main UK mobile phone network operators, said there was still no firm evidence of damage to health. "Successive studies have found no adverse health effects," she said.1. Based on the article, what was the hypothesis tested in this study? The hypothesis was that heavy cell phone use negatively impacts sperm quality. 2. What was the experiment designed to test the hypothesis? To test the hypothesis, researchers followed a group of 221 men over the course of 13 months, and compared sperm quality results of the men who used cell phones with results of those who did not. 3. What were the conclusions drawn from the results of the experiment? Experimental results showed that men who used their cell phones heavily had sperm count that was 30% reduced when compared to men who did not use cell phones heavily. Moreover, they also found reduced morphology in the surviving sperm of the cell phone users. Researchers then concluded that heavy cell phone use causes reduced sperm quantity and quality. 4. Are there alternative hypotheses that fit the data? One alternative hypothesis is that heavy use of cell phones correlates with a life style that causes reduced sperm quantity and morphology. 5. Based on the article, do you think the researchers proved their hypothesis true? Is the quote from Dr. Fejes justified given the data? Why or why not? Researchers did not design the experiment to address alternative hypotheses, nor did they perform follow up experiments to address such hypotheses. Therefore, we can not conclude that researchers proved their hypothesis true. Notice that in his quote, Dr. Fejes says that cell phone use “may have a negative effect,” rather than stating that it does. The statement as quoted is technically correct, given data. It is, however, significantly more modest than the claims the article makes about the study. 6. What follow-up experiments would need to be performed to validate the results of this study? One such experiment would be to find a group of men with as homogeneous a lifestyle as possible, who do not use cell phones on regular basis. To establish the baseline, test their sperm quantity and quality for a short time (say, two months), and exclude any who show bad results. Then randomly assign subjects to either the experimental or control groups. Subjects in the experimental group would then receive cell phones, and frequent calls on these cell phones from the researchers. Subjects in the control group would lead their normal lifestyle. If the subjects in the experimental group show a decrease in sperm quantity and quality, it would support the hypothesis that the cell phones cause reduced sperm quantity and quality. To further validate the hypothesis, another group of subjects who do not use cell phones a lot, but are put under stress would be informative. 7. Look again at the synopsis just below the title. Do you think it accurately describes the results of
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