Radiation from cell phones can damage sperm. Cell phone storage in front pockets has been linked to poor fertility and higher chances of miscarriage and childhood cancer.  According to the Cleveland Clinic Center for Reproductive Medicine, semen quality "tended to decline as daily cell phone use increased."  According to a May-June 2012 meta-study in the Journal of Andrology, "men using mobile phones have decreased sperm concentration" in addition to "decreased viability" of their sperm. 
It is useful to be aware of new health research regarding cell phone usage and cell phone radiation. The first cell phone call was made in 1985 and that phone cost $5,000 and weighed about 9 pounds. The change in size, weight and cost of devices today has probably led to over 50% of the human race owning a mobile device, the fastest growing technology on the planet.