Some scientific studies have suggested that the radio frequencies used by cell phones could have harmful effects on health, such as a decrease in sperm quantity and quality.
However, not all studies present the same results. This may be due to the presence of confounding factors, as for example has happened in the case of coffee, which has been associated in some studies with lung cancer.
The conclusion is that at present we cannot be certain that the use of cell phones affects sperm quality. However, there are studies that suggest it and it seems reasonable to recommend that patients who have sperm problems or who are going to undergo fertility treatment should, as far as possible, not abuse the use of these devices.