2007-10-16 07:20:10
Men who use laptop computers could be unwittingly damaging their fertility,
experts believe.
Balancing it on the lap increases the temperature of the scrotum which is known
to have a negative effect on sperm production, researchers found.
Coupled with the rising popularity of these computers - about 150m people use
them worldwide - much more research is needed say the US authors.
The State University of New York findings appear in Human Reproduction.
Teenage boys and young men may consider limiting their use of laptop computers
on their laps.
Lead researcher Dr Yefim Sheynkin
Lead researcher Dr Yefim Sheynkin, from the State University of New York at
Stony Brook, said: "Laptops can reach internal operating temperatures of over
70 C.
"They are frequently positioned close to the scrotum, and as well as being
capable of producing direct local heat, they require the user to sit with his
thighs close together to balance the machine, which traps the scrotum between
the thighs."
The researchers asked 29 healthy male volunteers aged between 21 and 35 to take
part in an experiment.
They then 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.
Heating up
When the men used a laptop in this position the average temperatures increased
by 2.6C on the left of the scrotum and 2.8C on the right.
It is worrying that having a laptop on your knees for only an hour can increase
the temperature of the scrotum so significantly.
Dr Allan Pacey of the British Fertility Society
Dr Sheynkin said: "The body needs to maintain a proper testicular temperature
for normal sperm production and development (spermatogenesis).
"We don't know the exact frequency and time of heat exposure capable of
producing reversible or irreversible changes in spermatogenesis.
"But previous studies suggest that 1 C above the baseline is the possible
minimal thermal gradient."
He said any changes might be reversible, but that repetitive use of a laptop in
this way might cause permanent damage.
"Until further studies provide more information on this type of thermal
exposure, teenage boys and young men may consider limiting their use of laptop
computers on their laps," he said.
Speaking on behalf of the British Fertility Society, Dr Allan Pacey, senior
lecturer in Andrology at the University of Sheffield, said: "We already know
that increasing the temperature of the testicles can affect sperm production.
"It is worrying that having a laptop on your knees for only an hour can
increase the temperature of the scrotum so significantly.
"Men who use laptops regularly should be very careful.
"Further work is needed to see if regular laptop use is a risk factor in male
fertility."