63 healthy and fertile men were divided into 4 groups, according to their daily usage time of the mobile phone (via questionnaire): 1) no mobile phone use (n=10), 2) <2 h/day (n=16), 3) 2-4 h/day (n=17) 4) >4 h/day (n=20). Group 4) was further subdivided into 4a) "trousers users" (n=12) and 4b) "shirt users" (n=8). Trousers users were considered the men who usually carry the phone in the pocket of the pants. Shirt users were considered the men who usually carry the phone in the pocket of the shirt.
Two semen samples from each subject were examined in the tests on semen quality.
all the examined subjects had used the same mobile phone device [UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz)] during the year before the study and reported that the device had been turned on 24 h of the day (data obtained by questionnaire)
None of the examined parameters showed significant differences between the groups except for DNA fragmentation in sperms. This was significantly increased in group 4 (>4 h mobile phone usage/day) compared to the other groups. Moreover, it was significantly increased in the sub-group 4a) "trousers users" compared to the sub-group 4b) "shirt users" within group 4.
The authors conclude that mobile phone use of more than 4 h/day, in particular if the device is carried in the pocket of the trousers, might result in DNA damage in sperms.