You see it everywhere -- in airport lounges, on park benches, even in offices. People balance their laptop computers on -- where else -- their laptops. For women this is not a problem, but a new study shows that it might decrease fertility in men.
It is well-established that raising the temperature in the scrotum, where sperm production takes place, can decrease fertility. That's why men who are trying to conceive should stay out of saunas, hot tubs and anything else that raises body and scrotal temperature. (Scrotal temperature is 2°C to 4°C below the man's body temperature. An increase of anything more than 1°C is considered significant enough to cause a problem.) When I spoke with the laptop study's author, Yefim Sheynkin, MD, associate professor of urology at the State University of New York, Stony Brook, he told me that although laptops do not raise body temperature, they nonetheless send heat directly to the scrotum. The result, as revealed in the study, is that use of them in the standard position does increase scrotal temperature.
In Dr. Sheynkin's study, researchers placed electronic sensors to relay scrotal temperatures every three minutes for 29 healthy men, ages 21 to 35, who sat in laptop-use position for one hour -- with or without the computer. Interestingly, even without computer-generated heat, sitting that long with their thighs closed raised the subjects' scrotal temperatures by 2.1°C. Computer use raised the temperatures an additional 0.7°C. The study did not evaluate how the heat affected semen or sperm production -- Dr. Sheynkin plans to study that later -- but based on findings from previous research, the rise in temperature here was sufficient to be alarming, since it can take several months after occasional hot-tub use for male fertility to return to normal. Imagine the impact of an activity that raises scrotal temperature for hours a day, day after day, year after year. Dr. Sheynkin stresses that he does not want to be an alarmist, but his study affirms for him the necessity of using a laptop on a desktop. Even placing it on a cushion in your lap, between you and your computer, won't help. The temperature rise created by the thighs-together position that supports the computer is in itself a possible risk. Admittedly, putting your laptop on a surface isn't as convenient, but this is where the better-safe-than-sorry cliché comes into play.