select search filters
roundups & rapid reactions
before the headlines
Fiona fox's blog

expert reaction to conference abstract looking at the effect of cell phone EMR on sperm motility and viability

A conference abstract (not a published paper) presented at the American Society for Reproductive Medicine 2022 meeting, looks at the effect of electromagnetic radiation (EMR) emitted by cell phones on sperm.


Prof Allan Pacey, Professor of Andrology at the University of Sheffield, said:

“This appears to be a well conducted laboratory study investigating the effects of 4G, 5G and wifi signals on sperm motility and viability in ejaculated human sperm. The data shows that sperm-exposure to wifi reduces sperm motility and viability. I have no problem with this conclusion on the basis of the information presented in this abstract, but we need to be cautious about how this is interpreted in a real world setting.

“First, it is important to note that sperm in the male body before ejaculation do not swim. Therefore, it is a leap of faith to assume that the damaging effects of wifi signals might affect unactivated sperm in men’s bodies in the same way as the authors of this study have shown for ejaculated sperm in the laboratory. This may be the case, but this study does not show this. I do not underestimate the technical difficulty in doing this kind of experiment on unactivated sperm that have not been ejaculated.

“Second, because sperm only begin to swim at the point of ejaculation, they are only really motile once they are inside the female body (in natural conception cycles) or in a cup or dish (if they are being used for assisted reproduction). Again, it is a leap of faith to assume that sperm inside a woman might be exposed to the same level of wifi signals used in these experiments. In assisted reproduction, it is not standard practice to have mobile phones in laboratories in close proximity to samples of sperm. Therefore, again, I am wondering about the real-life interpretation of this data.

“There is certainly reason to be concerned about threats to male reproductive health, but this study does not really help us with that question. It is an artificial experimental set-up and we should be careful not to over-interpret the results. What we lack is robust epidemiological data about mobile phone use and male fertility. In my opinion this should be our priority.

“Finally, the author claims that the impact of wifi on sperm has not previously been investigated, but I would like to draw attention to the paper: 

“Avendaño C, Mata A, Sanchez Sarmiento CA, Doncel GF. Use of laptop computers connected to internet through Wi-Fi decreases human sperm motility and increases sperm DNA fragmentation. Fertil Steril. 2012 Jan;97(1):39-45.e2. doi: 10.1016/j.fertnstert.2011.10.012.

“This showed similar results using wifi from a laptop computer rather than a smartphone.”


Prof Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said:

“My heart does rather sink when I’m asked to comment on a press release, like this one, for a conference paper. All I have to go on are the press release and a brief abstract (summary) of what the full research report will say. Usually, even if one goes to the presentation at the conference, there won’t be time for the presenter to give all the details necessary to assess the quality of the research. Anyway, the research won’t have gone through the full peer review process yet. I’m a statistician rather than an expert in radiation biology or in reproductive medicine, so I’d be commenting on the extent to which the design of the study and the statistical analysis support the conclusions that the researchers draw. But I simply can’t do that because there’s not enough information to go on.

“This affects all the reported findings – so maybe it is the case that using a phone for voice calls on Wi-Fi can affect sperm quality, or maybe it isn’t the case. And unfortunately, we can’t be reassured, from what’s been made available, that using 4G or 5G networks instead of Wi-Fi is safer for sperm quality, or that using a phone case (what sort of case?) or increasing the distance from the smartphone (by how much?) are safer. Maybe some or all of these things are indeed safer, but we’re not told enough to be able to tell.

“Also in this case the findings are from a pilot study. The idea of pilot studies is generally to provide a firmer basis for a larger, more definitive study, rather than giving anything that might be considered final results. Findings in pilot studies might or might not be confirmed when the larger study is done. So why are we being asked to consider these results from an incomplete research programme, on the basis of very incomplete reports?

“I should probably just leave my comment there, since I’m not going to be able to say anything at all definite, but I thought I’d explain in more detail just why I can’t make more definite points on the basis of the incomplete information.

“I think it does make sense to use an in vitro study, where possible effects of mobile phone radiation on sperm are investigated using sperm samples rather than in the bodies of men, or in a study using live animals. That’s because there could be issues with all the alternative types of study. A randomised trial would probably not be regarded as ethically possible. An observational study in humans, where the experimenters don’t change what the men would do anyway but simply record their phone use and sperm quality, would face the usual issue of potential confounding factors making it difficult to assess what’s causing what, and also it could well be difficult to measure the exposure to phone heat and radiation adequately. In an animal study, it’s always difficult to know how far the biology of the animals matches that of human males.

“But, though an in vitro study could tell us something, there are important questions about how the findings translate to what might happen with real humans using their phones in the way that humans do in real life. The results of this study do appear to indicate that putting semen samples near a phone, and using the phone for WhatsApp voice calls via Wi-Fi for six hours, can be associated with some issues in sperm quality. I can’t even be sure how appropriate those conclusions are, because I haven’t seen enough of the statistical details. But even if the findings are reliable enough, how similar is the set-up to what would happen in real life, where not many WhatsApp calls last six hours, but there could be many calls on many days; where the sperm in question are probably mostly in the user’s testicles, rather than having been ejaculated; and where the distance between the phone and the sperm might be very different from the situation in the experiment? I can’t say, partly because the details aren’t all given, and in any case it would need an expert in the relevant biology to assess whether the conditions in these in vitro experiments are close enough to what might happen in real life to be meaningful.

“Then there are important issues about what could be causing any effects on the sperm. The abstract and the press release both say that both the radiation and the heat from the phone contribute to the impact, but they don’t say why they come to this conclusion, or comment on the fact that it seems to be slightly different sperm parameters that were observed to change in the experiments with the phone and the experiments where semen samples were tested after being in an incubator. It’s perfectly possible that there is a good justification for concluding that both radiation and heat are involved, but we aren’t given any details on that. The incubator results do appear to indicate that too much warmth can affect sperm, but I believe that’s common knowledge, and the conclusion about radio frequency radiation seems more interesting – but were simply not told where it really comes from in the study.

“Finally there are statistical issues about uncertainty. The numbers of semen samples involved isn’t stated, except for the experiments on cases and distance from the phone, but it’s a pilot study so the numbers are likely to have been fairly small. That could mean that there are wide statistical margins of uncertainty about the results. The abstract says that the study was ‘adequately powered’, which means that the researchers considered that there were enough samples so that they had a high chance of detecting effects that they considered big enough to matter. But I haven’t seen the details of how they came to this judgement so can’t assess it.  And the margins of uncertainty aren’t given in the abstract. I do hope that there was adequate statistical power, but I can’t be sure of that on the information available. If, in fact, the study didn’t actually have enough statistical power, then the estimated size of the effects on sperm parameters is quite likely to be too large compared to the true effect size, and the fact that no effects were found with 4G or 5G signals may be because the study didn’t have the statistical power to find effects that actually exist, rather than because the effects didn’t exist or were too small to be of concern. But a judgement on all that will have to wait for the complete research report, and, more importantly, for results from the full study of which this is a pilot.”



“EFFECT OF ELECTROMAGNETIC RADIATION EMITTED BY CELL PHONES ON SPERM MOTILITY AND VIABILITY – AN IN VITRO STUDY”, by Kevin Chu et al; Conference abstract presented at the American Society for Reproductive Medicine 2022 meeting.



Declared interests

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  My quote above is in my capacity as an independent professional statistician.”

Prof Allan Pacey: Editor in Chief of Human Fertility, the Chairman of the Steering Committee for the UK National External Quality Assurance Scheme for Reproductive Sciences, a trustee of the Progress Educational Trust (Charity Number 1139856), and a Temporary Advisor to the World Health Organisation Guideline Development Group for global guidelines on the prevention, diagnosis and treatment of infertility (all unpaid). In addition, Allan is: (i) Chair of the Cryos International Scientific Advisory Board; (ii) a member of the Exceed Health Scientific Advisory Board; and (iiI) a member of the Cytoswim Ltd Scientific Advisory Board. But all fees associated with these are paid to the University of Sheffield and used to support teaching and research.

in this section

filter RoundUps by year

search by tag