Yes, electromagnetic radiation of cellphones can in fact affect several parts of the body, including the testes. In this case, the effects are more noticeable amongst males who are used to put their phone in their pocket.
Other factors to keep in mind are:
- Model or type of device
- Usage of Internet, if any
- Internet connection speed (3G or 4G)
- For how long the phone is kept in the pocket of the trousers
- Other places where the phone is kept
According to various studies, radiation of mobile phones affects the viability and motility of sperm. Sperm concentration is affected as well, though to a lesser extent.