According to a Microwave News report, a Californian researcher has found that daily magnetic field exposures of 1.6mG or higher for at least two-and-a-half hours were associated with significantly poorer semen quality. Men who were exposed to over 1.6mG for over six hours a day were four times more likely to have substandard sperm.  

Semen quality was assessed according to WHO criteria for motility and shape.  The researcher is quoted as saying that “sperm quality could turn out to be a sensitive endpoint to study the biological effects of EMFs. If it holds up, this would be very important because magnetic field exposures are ubiquitous. We know that sperm quality has been going down for a long time with the largest declines in urban areas. That would be consistent with EMF exposures which are highest in cities."  

The magnetic field levels implicated in this study are 1000 times lower than the current Australian and ICNIRP guidelines, but slightly above the threshold level of 1mG recommended by Building Biologists.  The report cites a large-scale survey carried out a decade ago, which found that close to 15% of the U.S. population is exposed to an average of more than 2mG over a 24-hour period.

Reference

Microwave News   2008   News and Comment : July 3   Online, available at : http://www.microwavenews.com

Baubiologie Maes    2003   Standard of Building Biology Methods of Testing (SBM-2003)   Online, available at : http://www.baubiologie.de/downloads/nglish/sbm2003_engl_new.pdf