A team of scientists has suggested that Wi-Fi-connected laptops sited too close to chaps' gonads could damage their sperm.
Argentinian and US boffins collected semen from 29 healthy males, divided each sample into two containers*, then exposed one "to an internet-connected laptop by Wi-Fi for 4 hours". The second sample "was used as control, incubated under identical conditions without being exposed to the laptop".
The results were that exposed samples "showed a significant decrease in progressive sperm motility and an increase in sperm DNA fragmentation". The researchers concluded: "We speculate that keeping a laptop connected wirelessly to the internet on the lap near the testes may result in decreased male fertility."
However, they note: "Further in vitro and in vivo studies are needed to prove this contention."
Fertility expert Dr Allan Pacey of the University of Sheffield agreed that more in vivo tests are in order. He told the BBC: "The study is very well conducted, but we should be cautious about what it may infer about the fertility of men who regularly use laptops with Wi-Fi on their laps. Ejaculated sperm are particularly sensitive to many factors because outside the body they don't have the protection of the other cells, tissues and fluids of the body in which they are stored before ejaculation.
"Therefore, we cannot infer from this study that because a man might use a laptop with Wi-Fi on his lap for more than four hours then his sperm will necessarily be damaged and he will be less fertile. We need large epidemiological studies to determine this, and to my knowledge these have not yet been performed."
Dr Pacey did, though, warn that sperm might be affected by "inadvertent testicular heating" from balancing a lappy on your lap for extended periods.
He concluded: "There is a case report of a man who burnt his penis after using a laptop resting on his lap for a long time. Therefore, there are many reasons to try and use a laptop on a table where possible, and this may in itself ameliorate any theoretical concerns about Wi-Fi."
The penis-burn laptop shocker in question was back in 2002, when a 50-year-old scientist scorched his wedding tackle after one hour tapping away on what was allegedly a Dell.
He suffered "penile and scrotal blisters", but no lasting damage. ®
* Aliquots, actually. Lovely word.