To test the theory, Argentinian researchers put drops of healthy sperm near a laptop downloading data. After four hours, a quarter of the sperm had stopped swimming, compared to 14 percent of sperm in the control group placed away from the computer. In addition, 9 percent of sperm near the computer had DNA damage, three times more than the sperm in the control group.

The culprit? Electromagnetic radiation from the wireless internet, noted the scientists. Still, they say at this point the results are not conclusive until more research can be done.

In another study published in the same journal, US researchers placed temperature sensors on the scrotums of 29 men. The men set to work using laptop computers on their laps, and after 10 to 15 minutes had elapsed, scrotum temperatures rose to levels known to damage sperm production.

For maximum sperm production, testicles need to remain cool, even one to two degrees below body temperature. Using a laptop computer can cause temperatures to rise by 2.5°C in one hour, according to the study.

One way around this problem? Use a desk. Or try a laptop pad and keep your legs apart, but men, this will only buy you 20 minutes before your testicles heat up to sperm-killing temperatures, according to the study's lead urologist Dr. Yefim Sheynkin of the University of New York at Stony Brook.