Is Pollution Really Causing Male Fertility to Decline?

Male fertility is under attack. One Danish study found that sleep deprivation reduced not only sperm concentration and quality but testicle size as well. Other studies have blamed chemical compounds that mimic female hormones, commonly found in fertilizers and insecticides. Even compounds found in cleaning fluids and perfumes have been accused of having “gender-bending” properties that can seep through into our water.

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“The decline in sperm quality is a global process,” says Dr. Shahar Kol, director of the artificial insemination clinic at the Rambam Medical Center in Haifa. The world’s answer hasn’t been to mend its ways but to lower its standards – “rather like the ‘bottom red line’ of the Sea of Galilee’s water level,” he chuckles. “Four years ago the World Health Organization itself lowered the threshold minimum of proper sperm from 20 million cells per milliliter of ejaculate to 15 million.”

Not all agree as to the significance of the WHO move. “The sweeping statement that male fertility is deteriorating is controversial,” wrote Prof. Eitan Lunenfeld, past president of the Israeli Fertility Society and chairman  of the Ob-Gyn Department at the Soroka Medical Center, Faculty of Health Sciences,  Ben-Gurion University of the Negev, in an email interview.

In recent years the WHO reset its sperm testing standards according to the ability to conceive through a one-year period: But the fact that its parameters are lower than in the past does not necessarily attest to a decrease in male fertility, Lunenfeld avers.

Dr. Eliahu Levitas, head of the IVF unit at the Soroka Medical Center, Ben-Gurion University of the Negev, goes one farther. He can’t stand the popular penchant for Apocalypse Any Second Now, and stresses that there are no meta-studies out there indicating that male fertility is truly declining. There are certainly plenty of indicators, but the studies on feminized fish or fertility-challenged truck drivers are isolated instances, he says. Even the WHO’s move to lower its criteria of “normal morphology” from 14% of the sperm to 4% doesn’t indicate a problem with male fertility per se. It just means that, armed with better technology and tools, they refined their criteria, says Levitas.

Sperm stats certainly aren’t the be-all and end-all of fertility, all three professors agree. They also agree that pollution, a particularly pervasive problem in the West, could change all that.

Eggs instead of sperm in their testes

Indeed, the stats are all over the place. A French study on fertile men done over 20 years, published in 1995, found a decline in the concentration and motility of sperm, and in morphologically normal spermatozoa. A Chinese meta-study published in 1999 on sperm changes from 1983 to 1996 showed a decrease in the mean concentration of sperm, a decrease in sperm motility and a drop in the percentage of sperm with normal morphology. A smaller analysis done on 1,283 American men published in 1996, tracking men over 25 years, found no change whatsoever.

There is no argument that male fertility is threatened by pollution and lifestyle changes, but that doesn’t mean the problem is global rather than localized. Also, the statistics have to be interpreted carefully: Not every seeming drop in sperm count, motility or whatever translates into infertility, Lunenfeld explains.

“Take the example of men with infertility because of inadequate gonadotropin production,” Lunenfeld says. Gonadotropin therapy can boost sperm counts caused by low levels of the hormone. “Their sperm counts – even before reaching the standards set by the WHO – can certainly fertilize an egg inside the body and bring healthy children into the world,” he says.

So while moaning about the pollution behind unsettling phenomena like micro-penises in Florida alligators, the masculinization of female marine snails and male fish with eggs instead of sperm in their testicles is all the rage, at the end of the day these examples cannot be taken as the bigger picture of male fertility. Nor do statistics tell the whole story: “Fertility is a function of the ability to achieve pregnancy, not statistical tests of sperm,” explains Lunenfeld.

Sperm may look lousy but do the trick, and conversely, some sperm looks terrific and meets all the standards but nothing happens unless the sperm is physically injected into the egg.

How God created sperm

Whatever the cause, the answer for barren couples isn’t going to lie in cherry-picking a donor – not even insisting on the donor being an Israeli combat soldier, as has happened at the sperm bank Kol runs. The donor may have personality qualities that the would-be parents want in a child but his sperm won’t necessarily be superior.

Also, a man may be as fertile as a rabbit and still not suit as a donor. Only about 10% of would-be donors qualify for the sperm bank. Kol explains why. “In most cases it isn’t because of some problem with the sperm quality. The problem is that the sperm doesn’t pass the freezing-thawing test,” he says.

Other countries may allow use of fresh sperm but Israeli sperm banks only use frozen (and thawed) cells, he explains, mainly to protect against disease.

Would-be donors first have to be tested for dangerous viruses, such as AIDS and hepatitis. If found clean, the donation is taken and frozen for at least three months, after which the donor is retested.

The reason is that a freshly-infected man may test healthy the first time but after three months, even if he’s completely asymptomatic, the disease will have manifested itself in his immune system. If disease is found in the second test, the man is barred from sperm donation.

“The thing is that sperm wasn’t created by God, or evolved, whichever you believe, to be frozen to a temperature of minus 196 degrees in liquid nitrogen. Nor was it created or evolved to be examined through a microscope,” says Dr. Kol. “Sperm may look fantastic under the microscope, and have the right concentration, but the man still may not be fertile.”

They see that at IVF labs. “Couples come in and do all the tests and we find that the man’s sperm is fine. But when you put this sperm that looks fantastic with the eggs – nothing happens. And vice versa,” Kol says. “The numbers may look terrible but the man may be perfectly fertile.”

So a combat soldier may have all the right stuff, in every way, but his sperm may not pass that unnatural process of freezing and thawing.

Gonad-coolers for taxi drivers

Sperm has other challenges in the modern world.

“Most of our days we were hunter-gatherers. We were racing to hunt animals on our two legs, or were racing from animals who wanted to hunt us,” says Kol. “Now, certainly in the West, most men work sitting down. But sitting down is not what God or evolution meant us to do.”

Male infertility can have different origins, from low to zero sperm production in the first place, to production of abnormal sperm, to physical blockages that prevent the sperm from being delivered. One doesn’t have to be born infertile: Different things from illness to lifestyle choices can cause the condition. Such as being a taxi driver.

“Why do the testicles dangle outside the body?” Kol asks. “To keep them cooler than the core body temperature. But if you’re sitting down, that doesn’t happen.”

The hypothesis that being seated for hours raises scrotal temperature was proved in 2000 by a French team that attached little thermometers to the junk of Parisian drivers. They had the nine volunteers walk outside for 40 minutes, then drive for 160 minutes, and recorded their scrotal temperature every two minutes. Indeed, the temperature of their testicles rose significantly – by as much as 2.2 degrees – after they’d been driving for two hours.

Similar studies done on taxi drivers in Italy and professional drivers in Hungary found that among men seeking help for infertility, a higher proportion drove for a living than among the general population. There is no question that the hotter the environment, the worse sperm feels. “Sitting down for a living bears a price,” observes Kol.

And there’s also no telling what the future may bring. On the one hand, the apocalypse crowd wails that the planet is just growing fouler; on the other, Dr. Levitas points out, awareness coupled with technology is improving mankind’s waste management. “We all have a feeling that all this pollution has to have an effect at some point, but has it already done so?” he asks. “That, we can’t say.”