Cell phones are used by at least 700 million people worldwide, and, of course, there has been speculation about their possible effects on health. Brain cancer has been investigated and the verdict is conflicting - in a small study in Sweden there seems to be a positive risk, while other studies are negative, though doubt persists.

A finding that's probably going to alarm people far more than the others has just been reported in the journal Fertility and Sterility.

Doctors at a fertility clinic in Ohio assessed the effects of cell phone use on sperm quality in 361 men who were having infertility tests. The men were divided into four groups based on reported daily cell phone use: no use; less than 2 hours; 2-4 hours; and more than 4 hours. Analysis showed that the sperm count, motility, viability, and normal morphology differed among the four groups. The sperm motility, viability, and morphology (appearance) were decreased in the cell phone users as cell phone usage increased. One problem with this study is the failure to control for other factors that might influence the link between cell phone use and semen quality (e.g. occupation, drug use). Still, this finding must be explored further with more elaborate studies, using different populations, occupations, and men not being evaluated at fertility clinics.

In the meantime, however, this report may, just, have the beneficial effect of reducing cell phone usage in public places that often irritates those in hearing range while probably not satisfying the recipient.