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Sperm Count
Waterbeds and electric blankets are bad for sperm, but computer terminals, marijuana and job stress appear to protect a man's ability to father a child, new research shows.
 As well, while men who drink alcohol are more likely to be infertile than those who abstain, researchers could find no link between smoking, exercise, shift work, electromagnetic fields, solvents, lead, paint, pesticides, vibration or caffeine use and male infertility.
Jacuzzis and space heaters also appear to be harmless to sperm.
"Except for heat exposures consisting of waterbed and electric blanket use, environmental factors in men are weakly associated, if at all, with infertility in men," according to the study by University of Rochester researchers.
Fertility HelpThe findings were released Tuesday at the annual meeting of the American Society for Reproductive Medicine, the world's largest gathering of doctors, researchers, nurses and other professionals in reproductive biology.
A Canadian expert on sperm criticized the study as "superficial," saying it contradicts better research that has found clear links between environmental toxins such as pesticides and male infertility.
Dr. David Mortimer also said the study doesn't detail the degree of exposure -- meaning how much the men were exposed to paint and other chemicals, and how often.
Mortimer, a consultant to fertility clinics in Victoria, Halifax and around the world, said men who spend a lot of time on computers may have a lower likelihood of infertility simply because they are less likely to be in jobs that expose them to harmful chemicals.
He said heat is known to damage sperm. "The reason the testes dangle where they do is because they need to function at two degrees lower than the core body temperature," he said.
Previous studies have found environmental and lifestyle factors such as smoking can affect "semen parameters," meaning sperm count and motility. But it's not clear whether they actually harm a man's ability to have children. The new study is based on data that was collected as part of a large study involving 650 infertile couples and 698 fertile couples who were recruited from university-based infertility and prenatal clinics. Infertility CausesCases included infertile males whose partner passed a normal fertility evaluation, and fertile men who had had a child, or made their partner pregnant, within two years of the study.
The men were aged 20 to 55. Any men with a history of chemotherapy, previous surgery or a medical condition that might cause infertility were excluded.
Researchers found infertile men were more likely to be Caucasian, blue-collar employed and less educated than fertile men.
Electric blankets were associated with a 7.4-fold increased risk in infertility, while waterbeds increased the risk more than four-fold.
On the other hand, men who were exposed to computer terminals, marijuana, job-related stress and radiation were half as likely to suffer from infertility compared to men who didn't report those exposures.
The researchers caution the study relied on men to remember what they had been exposed to.
They said larger studies are needed to clarify the association between environmental exposures and infertility "before widespread behavioral modification is recommended."
Paul Ellis - Men's Health
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