“We’re not seeing an epidemic of 50-year-old businessmen with testicular cancer."

Q. Can laptops cause infertility or even (gulp) cancer in men?

A. I found this question posted all over the Web: on women’s fashion sites, Yahoo boards and even video game sites, where most of the postings (and rife spelling mistakes) were likely written by teens.

Some noticed that the word “laptop” has fallen curiously out of style, in favor of “notebook computer.” So did the “lap” leave on account of a hidden health hazard?

The two overriding concerns are whether laptops, through either their heat emissions or radiation, can lead to male infertility or testicular cancer. Let’s dive in.

Q. So what about cancer?

A. It is common for most people to associate “radiation” with “that’s going to kill me.” Some high-profile cases helped put the issue on the map, including the early 1990’s finding that radar guns were causing police officers testicular cancer, or the still-debated study linking high power lines to childhood leukemia.

This in spite of the fact that everything from your car’s engine to hair dryers to you yourself are producing radioactive energy. It all depends on what type of radiation we’re talking about. Laptops generate electro-magnetic fields known as “extremely low-frequency radiation,” or ELM. They generate them all directions, not just from below or through the screen.

ELM radiation is known as non-ionizing radiation, far different from the ionizing radiation given off by nuclear reactors or the plutonium from the “Back to the Future’s” Flux Capacitor. Non-ionizing radiation, according to Illinois’ Argonne Labs and other scientific authorities, should have “little effect on DNA, RNA, or other cell components.”

So is there a link between laptops and cancer?

“Overwhelming evidence is that there is not,” said Dr. Boris Pasche, oncologist and geneticist at Northwestern University’s Robert H. Lurie Comprehensive Cancer Center.

“There is not a great incentive to look into it,” added Dr. Timothy M. Kuzel, who directs the Lurie Center. He called alarmist data to the contrary “highly debatable.”

Laptops are safe to use, Kuzel said; he’s a laptop user himself.

One reason for the confusion: Kuzel said that testicular cancer “almost exclusively” targets young men ages 16 to 30, a group that, nowadays, also tends to use laptops.

“We’re not seeing an epidemic of 50-year-old businessmen with testicular cancer,” Kuzel said.

Pasche didn’t rule out the possibility of a connection between laptops and cancer, however. “It will take a very long time to find out if there is a relationship or not… When everybody uses a laptop, it is very difficult.”

Q. And infertility?

A. Pasche said a much larger concern involves laptop heat emissions and “a decrease in spermatogenesis,” or the production of healthy male sperm.

The issue was given considerable ink in 2004, when a U.S. study printed in the leading medical journal Human Reproduction said that laptop heat can raise scrotal temperatures up to five degrees, a significant difference.

The study found that “significant but reversible changes” in sperm production resulted from short-term laptop use. However, using a laptop often day after day doesn’t give the body a chance to recover from heat exposures, and “may cause irreversible or partially reversible changes in male reproductive function," the study said.

U.S. news outlets trumpeted the news, with headlines like “Doctors warn young men: Get the laptop off your lap!”

However, a leading fertility doctor in Chicago isn’t overly concerned right now.

“I would view it as an anecdotal report,” said Dr. Edmond Confino.

Confino, who is reproductive endocrinologist and infertility doctor at Northwestern University’s Feinberg School of Medicine, said the knowledge that heat and infertility are connected goes back to Roman times (they noticed hot bath frequenters had trouble bearing children).

Men’s testicles are very temperature-sensitive – they hang away from the main body to keep their temperature a few degrees cooler than the body’s “core temperature.”

However, Confino said the study was far from authoritative, and he is still unsure if the heat from laptops is really enough to affect male sperm.

“It needs more work,” he said.

Conclusion:

Looks like a little bit of “laptopping” is fine – don’t tackle your friends if you see them powering up a laptop on their lap. After a long spell, though, it might not hurt to give yourself a break.