Men who use laptop computers could be unwittingly damaging their fertility, scientists claim.
Balancing it on the lap increases the temperature of the scrotum, which is known to have a negative effect on sperm production, researchers found. These findings along with the rising popularity of these computers - about 150m people use them worldwide - much more research is needed say experts from the State University of New York.
During the experiment the researchers recorded the temperature changes to the scrotum caused by laptop use and different seating positions over one hour time periods. Just sitting with the thighs together, a posture needed to balance a laptop, caused scrotal temperatures to rise by 2.1C.
The head of the researches team Dr Yefim Sheynkin warned that repetitive use of a laptop in this way might cause permanent damage.