Do phones, laptops and Wi-Fi affect sperm?

For phones and Wi-Fi, the evidence is weak and the most careful recent review calls it very uncertain. A 2024 review commissioned by the World Health Organization pooled the human studies and could not tell whether phone use changes sperm count, motility or shape, and found that carrying a phone in a front pocket may have little or no effect [1]. Older meta-analyses that mixed lab experiments on sperm in a dish with studies of men did report lower motility [4, 5]. Laptops are different: the clearer issue is heat, not radiation. In a 2005 study, sitting with a working laptop on the lap raised scrotal temperature by 2.6 to 2.8°C, against 2.1°C from the same posture without one [7]. Put the laptop on a desk; the phone in your pocket is a much smaller worry than the things with stronger evidence.

What the worry is

Phones, laptops and routers send and receive radiofrequency electromagnetic fields (RF-EMF). The concern is that sperm, made in the testes near where a phone sits in a pocket, might be affected by that exposure. It is a fair question to ask, and it has been studied in three ways: men's phone habits compared with their semen results, human sperm exposed to a phone or laptop in a dish, and animal experiments.

Phones: what the studies of men found

The WHO-commissioned review. In 2024 the WHO had systematic reviews done on radiofrequency exposure and health, to inform its exposure guidelines. The review of human observational studies on male fertility (Environment International) found nine studies and graded the evidence on phone use and sperm concentration, morphology, progressive motility and total count as very low certainty [1]. Per extra hour of daily phone use, the pooled change in concentration was 1.6 million per mL, with a range from 1.7 lower to 4.9 higher, so no clear effect either way. Carrying a phone in a front pocket "may" have little or no effect on concentration, total count, morphology, progressive motility or time to pregnancy.

The largest single study. Rahban and colleagues (Fertility and Sterility, 2023) studied 2,886 Swiss men aged 18 to 22, recruited at military conscription between 2005 and 2018 [3]. Men who used their phone more than 20 times a day had a lower total sperm count, and a 21% higher chance of a total count below the WHO reference value; the link with concentration was weaker and not statistically clear. The link was strongest in the earliest years of the study and faded over time, which the authors connect to newer phones putting out less power. Keeping the phone in a trouser pocket was not linked to lower results, and there was no consistent link with motility or shape. The authors say prospective studies are needed before anyone can call it causal.

Older meta-analyses. A 2014 meta-analysis of 10 studies and 1,492 samples found phone exposure was linked to motility about 8 percentage points lower; the drop in viability (about 9 points) had a range that included no difference, and the effect on concentration was "more equivocal" [4]. A 2021 update of 18 studies and 4,280 samples also reported lower motility, viability and concentration, but the drop did not get bigger with more phone use, and the authors called for studies of newer phones [5]. Both pooled lab experiments on sperm in a dish with studies of men, and in the 2014 review the men came from fertility clinics and research centers.

Wi-Fi and laptops

Heat. Sheynkin and colleagues (Human Reproduction, 2005) measured scrotal temperature in 29 men with a working laptop on their laps: it rose by 2.8°C on the right and 2.6°C on the left, against 2.1°C from sitting in the same position without the laptop [7]. Sperm production works best a couple of degrees below body temperature, which is why the heat guide is the place to start with laptops.

Wi-Fi. A 2012 lab study put sperm from 29 healthy donors in a dish under a laptop connected to Wi-Fi for four hours, and found lower progressive motility and more DNA fragmentation than in sperm kept away from it, with no difference in the share of dead sperm [6]. The authors speculated about laptops on laps but said further studies were needed; sperm in a dish under a laptop for four hours is not the same as sperm in the body. The WHO-commissioned review of human studies found one study on computers and other devices, which suggested little or no effect [1].

What the lab and animal studies add

A second WHO-commissioned review (Environment International, 2024) covered 117 animal studies and 10 studies of human sperm exposed in a dish [2]. For human sperm in a dish it found a small drop in vitality and no effect on DNA, both at very low certainty. The animal studies pointed to harm on several measures, rated moderate certainty only for a lower pregnancy rate and low or very low for the rest, and most used exposures higher than people typically get and above the limits in international guidelines, and the review could not show a consistent link between exposure level and effect.

So does it matter?

The honest summary: nobody has shown that normal phone or Wi-Fi use lowers fertility, and the best-conducted review says the evidence is too uncertain to tell. The one large study that found a link also found it fading as phones changed. If you want to remove any doubt, keeping your phone somewhere other than a trouser pocket costs nothing. But the time and attention are better spent on the factors with stronger evidence: not smoking, keeping the testes cool, and drinking moderately, which the main guide ranks.

What to do

• Put the laptop on a desk or a lap tray. That is about heat, and it is the part with the clearer evidence.
• Don't worry about the router or ordinary Wi-Fi at home. The only worrying result came from sperm in a dish sitting under a laptop for four hours, and nothing in studies of men points to a problem.
• If you'd like to, keep your phone in a bag or jacket rather than a trouser pocket. The evidence doesn't say you need to, and it costs nothing.
• Break up long stretches of sitting with the legs together, which warms the testes on its own.
• Put your effort where the evidence is stronger: smoking, heat, alcohol and weight. The main guide ranks them.

Questions

Related

• Heat: saunas, hot tubs, laptops and underwear
• Every factor ranked
• Microplastics and sperm
• Male infertility statistics

Sources

1. Kenny RPW, et al. The effects of radiofrequency exposure on male fertility: a systematic review of human observational studies with dose-response meta-analysis. Environment International, 2024.
2. Cordelli E, et al. Effects of radiofrequency electromagnetic field (RF-EMF) exposure on male fertility: a systematic review of experimental studies on non-human mammals and human sperm in vitro. Environment International, 2024.
3. Rahban R, et al. Association between self-reported mobile phone use and the semen quality of young men. Fertility and Sterility, 2023.
4. Adams JA, et al. Effect of mobile telephones on sperm quality: a systematic review and meta-analysis. Environment International, 2014.
5. Kim S, et al. Effects of mobile phone usage on sperm quality: no time-dependent relationship on usage. A systematic review and updated meta-analysis. Environmental Research, 2021.
6. Avendaño C, et al. Use of laptop computers connected to internet through Wi-Fi decreases human sperm motility and increases sperm DNA fragmentation. Fertility and Sterility, 2012.
7. Sheynkin Y, et al. Increase in scrotal temperature in laptop computer users. Human Reproduction, 2005.