Friday December 2 2011
The use of wi-fi has rocketed in recent years
“Working on a laptop wirelessly may hamper a man’s chances of fatherhood,” the Daily Mail has today reported. Its story is based on a laboratory study that found that healthy sperm placed under a laptop connected to the wireless internet for four hours, showed less movement and more changes to their genetic code than ‘control’ sperm not near a wi-fi connected laptop.
Men should not be too concerned by the findings from this preliminary laboratory study, as they are not proof that using a wireless laptop on the lap reduces male fertility. It is simply not possible to draw conclusions about the possible effect of wi-fi on male fertility from a laboratory study that involved sperm taken from only 29 donors.
As one expert pointed out, sperm in the laboratory are outside the human body and do not have the protection of the tissues and fluids of the testes in which they are stored. Therefore they might be more vulnerable to damage.
It is also not clear whether the effects seen would be sufficient to affect fertility. Further studies are needed before it is known what effect, if any, exposure to wi-fi has on sperm in the body or on male fertility.
Where did the story come from?
The study was carried out by researchers from Nascentis Reproductive Medicine in Argentina and the Eastern Virginia Medical School in the US. The study was published in the peer-reviewed journal Fertility and Sterility. No external funding sources were reported.
In its report, the BBC appropriately pointed out that this was preliminary research and further studies are needed. The story also carried a lengthy critical assessment from an independent expert pointing out why the research may not reflect what happens in a real-life setting.
The Daily Mail explained how the study was conducted and includes comments on its limitations from an expert. Its headline that ‘Radiation from wi-fi connections can reduce sperm activity in up to a quarter of men’ may suggest that the study was carried out in humans, which is not the case.
What kind of research was this?
This was an experimental laboratory study looking at how sperm samples were affected by exposure to a nearby laptop wirelessly connected to the internet. The sperm samples were donated prior to exposure to wi-fi, meaning the study looked at particular sperm isolated from their normal environment.
Studies that look at components of an organism outside of their biological context are called ‘in vitro’ studies, which literally means studies ‘within glass’ due to their use of apparatus such as test tubes and Petri dishes. They differ from ‘in vivo’ studies, which look at what occurs in a living organism such as a person.
The researchers point out that people using wi-fi may be exposed to radio signals by absorbing some of the transmitted energy in their bodies. They say that portable laptops, positioned in the lap, may expose the genital area to radio-frequency magnetic waves (RF-EMW) as well as high temperatures. They mention the suggestion that male fertility has declined in recent decades, and that this may be attributed to exposure to environmental factors such as RF-EMW.
This type of study is an appropriate first step to look at whether wi-fi laptops might damage sperm, but cannot fully represent what would happen in real life. Further studies in humans would be needed to determine whether use of wi-fi laptops can affect fertility.
What did the research involve?
The researchers collected 29 semen samples from healthy donors aged between 26 and 45. They measured each sample’s number of sperm, the sperm’s ability to swim (motility) and its shape (morphology), all of which demonstrate the quality of the sperm. Using special techniques they isolated the healthiest moving sperm for the study.
Each of the 29 samples was centrifuged to form a ‘sperm pellet’ and then divided into two Petri dishes. One dish was stored for four hours at room temperature under a laptop computer connected to the internet by wi-fi. The laptop was set to constantly transmit and receive data via wi-fi. The distance between the samples and the laptop was 3cm, which researchers estimated as the distance between a computer resting on the lap and the testes.
The other dish was stored under similar conditions and also at room temperature, but in a separate room away from any computers or other electronic devices. Both sets of sperm samples had their temperature recorded every five minutes.
After four hours, researchers measured all the samples for sperm vitality and motility. They also looked at whether the sperm’s DNA (its genetic code) had been damaged, by looking at the level of breakage in the DNA.
What were the basic results?
At the start of their study, most of the sperm samples were normal, although samples from three men were low in semen volume and three contained abnormally shaped sperm.
When they compared the sperm exposed to wi-fi from a laptop to those not exposed, they found that:
- the percentage of dead sperm was no different between the samples exposed to the laptop and the control group
- a smaller percentage of the sperm exposed to the laptop wi-fi had the ability to swim forward (68.7%) compared with the control sperm (80.9%)
- there was no difference between the groups in terms of the percentage of sperm that could move but not move forward effectively
- more sperm exposed to laptop wi-fi did not move at all (24.5%) compared to the control sperm (13.6%)
- sperm exposed to the laptop wi-fi had higher levels of DNA damage, with 8.6% of sperm showing fragmented DNA, while only 3.3% of the control sperm showed fragmented DNA
How did the researchers interpret the results?
The researchers conclude that laptop computers connected wirelessly to the internet reduced the quality of sperm and induced DNA damage in the laboratory. They say the findings suggest that prolonged use of portable computers on the lap may reduce male fertility and this warrants further investigation.
This small laboratory study found that the movement and DNA of sperm outside of the human body may be affected by close exposure to a laptop connected to the internet by wi-fi.
While the findings of this lab-based study suggest that the effects of wi-fi on sperm may be worth investigating further, its findings should be interpreted in context:
- It did not directly examine the way wi-fi affected the testes, sperm while still inside the testes or male fertility. On this basis it cannot show that any of these factors are directly affected by laptop use.
- As one expert has pointed out, the tissues and fluids of the body protect the sperm, and sperm stored and tested outside the human body do not have this protection. The sperm examined in this study might therefore be more vulnerable to damage.
- The study was relatively small, testing sperm from only 29 men.
- The majority of sperm in both the wi-fi and control conditions could still swim normally.
- Even if wi-fi does reduce the number of sperm in a real-life setting, this may not have any impact on the ability to conceive.
- The semen in the study was processed ahead of testing; for example, being centrifuged to produce a concentrated sperm pellet. This may have influenced the way that sperm were affected during the test.
- Heat is known to affect sperm, but temperature testing was performed every five minutes rather than continuously. Although an air-conditioning system was used to regulate the temperature, it is possible that there may have been brief spikes in the operating temperature of the laptop that were not accounted for by this periodic reporting.
- The researchers suggest that the operation of the laptop, rather than its wi-fi signal, might be affecting the sperm in some way. However, the study did not test samples exposed to a laptop not using wi-fi. This would have been useful to tell whether wi-fi exposure itself was responsible for these changes or if it was something else relating to the laptop.
Studies following men in the general population would be needed to investigate whether wi-fi connected laptops have any effect on male fertility.