Increase in scrotal temperature in laptop computer users.

Plain-language summary

This study set out to measure how much using a laptop on your lap raises scrotal temperature, a known risk factor for male infertility. Researchers measured scrotal temperature in 29 healthy men over two separate hour-long sessions, one with a working laptop on their thighs and one sitting the same way without it. Scrotal temperature rose in both sessions. With the laptop it rose 2.8 degrees Celsius (5.0 degrees Fahrenheit) on the right and 2.6 degrees Celsius (4.7 degrees Fahrenheit) on the left, and sitting with the thighs together without a laptop it rose 2.1 degrees Celsius (3.8 degrees Fahrenheit). The rise with the laptop was the larger of the two, so posture and the machine both contribute.

Key findings

• With a working laptop, scrotal temperature rose 2.8 degrees Celsius (5.0 degrees Fahrenheit) on the right side and 2.6 degrees Celsius (4.7 degrees Fahrenheit) on the left.
• Sitting the same way with the thighs together and no laptop raised it 2.1 degrees Celsius (3.8 degrees Fahrenheit).
• The rise with the laptop was higher than the rise without it. The paper reports the two rises separately and does not report the difference between them.
• The authors expect long-term repeated heating of this kind to harm sperm production, particularly in teenage boys and young men.