Office jobs 'can make men infertile'

Men whose jobs involve sitting down for more than six hours a day may be reducing their chances of fathering children.

Men whose jobs involve sitting down for more than six hours a day may be reducing their chances of fathering children.

Researchers, who have designed special thermometers to fit into male underpants, found that sitting down for more than one hour led to significant increases in scrotal temperatures, something that is been linked to poorer-quality sperm.

"A high scrotal temperature is a common finding in infertile patients, and experimental studies indicate that specific types of heat exposure reduce semen quality," say the researchers.

"More and more men have a sedentary work position, which increases scrotal temperature. Normal sperm production depends on a testicular temperature below body temperature."

In the research, reported in the journal Reproductive Toxicology, doctors developed a "thermisor" that was attached to the underwear of 100 men, and a portable device logged the temperature of the scrotal skin every five minutes for 24 hours. At the end of the exercise, temperature was matched with what the men were doing at the time.

The researchers found that there was a difference of almost two degrees Celsius between men who sat for less than one hour and those who sat for longer than six hours.

The testicles need to be cooler than normal body temperature so they can successfully make sperm, which are highly sensitive to warm temperatures. It is thought that when sitting for a prolonged time, the testicles are drawn up close to the body resulting in an increase in temperature. Although the problem is growing because of the numbers of men now in office jobs, there is no obvious solution.

One possibility is that men who are trying to father a child could be temporarily reassigned to jobs where there is more physical activity.

Another idea is that men who want to be fathers should get up and walk around every 30 minutes to lower their testicular temperature.