From the Beeb:

Heavy mobile use 'damages sperm'

Experts are calling for further research into the effect of mobiles on fertility Heavy use of mobile phones may damage men's fertility, a study has suggested. Researchers found those men who used a phone for four hours or more a day had fewer sperm and those they had moved less well and were of poorer quality. The Ohio study involving 364 men was presented to the American Society for Reproductive Medicine in New Orleans. But a UK expert said it was unlikely the phones were to blame, as they were in use and not near the testes, and it may be being sedentary was the cause.