A study by Israel's Technion Medicine and Carmel Medical Center found a link between cell phone usage and sperm quality.
They studied 106 men for a full year and found 47% of those who kept phones in their pants pocket had low sperm counts, compared to 11% of the general population.
Men who used their phones while charging, talked on them for more than an hour a day and those who slept with phones near their bedside also had significantly lower sperm counts.
Professor Martha Dirnfeld, of Technion University, said, "We think this is being caused by a heating of the sperm from the phone and by electromagnetic activity."
Dr. Ariel Silberlicht of Carmel Medical Center recommends keeping phone calls short, carrying phones in a pocket away from the groin area, and keeping phones at a distance while sleeping.