The legislators themselves say that no link has been demonstrated (Le Monde reports them as having been unable to identify ‘a causal link between the biological effects described on cellular models, animals or humans and possible health effects that result.’) and there is only limited evidence (one study, unconfirmed by any others) to suggest risk even for intensive users of mobile phones.
The purpose of the study was to investigate the effect of 2.45 GHz microwave radiation (2 h/day for 35 days) on the male rat brain. MWR-exposed rats showed significantly increased comet head, tail length and tail movement, as well as decrease of antioxidant enzymes. Researchers conclude that the chronic exposure to these radiations may cause significant damage to brain, which may be an indication of possible tumour promotion.

In response to public concern, the WHO established the International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. They have stated that although extensive research has been conducted into possible health effects of exposure to many parts of the frequency spectrum, all reviews conducted so far have indicated that, as long as exposures are below the limits recommended in the ICNIRP (1998) EMF guidelines, which cover the full frequency range from 0–300 GHz, such exposures do not produce any known adverse health effect.[2] Stronger or more frequent exposures to EMF can be unhealthy, and in fact serve as the basis for electromagnetic weaponry.
METHODS: Standard class V cavities were prepared on the buccal surfaces of 20 non-carious extracted human premolars. The teeth were randomly divided into 2 groups (n = 10). The control group was stored in non-environment. The specimens in the experimental groups were exposed to a radiofrequency radiation emitted from standard Wi Fi devices at 2.4 GHz for 20 min. The distance between the Wi-Fi router and samples was 30 cm and the router was exchanging data with a laptop computer that was placed 20 m away from the router. The concentration of mercury in the artificial saliva in the groups was evaluated by using a cold-vapor atomic absorption Mercury Analyzer System. The independent t test was used to evaluate any significant differences in mercury release between the two groups.
Listeria monocytogenes response to each antibiotic was different, for DOX (doxycycline), and the window response occurred after 6 hours of exposure to Wi-Fi and RF simulator radiation. However, for other antibiotics, these changes were only observed at the ninth hour of exposure to Wi-Fi while this response could not be observed for RF simulator radiation. After 9 hours of exposure to Wi-Fi for CIPR and SXT antibiotics, bacteria had a tendency to become more resistant. This was in contrast to the pattern observed for LEVO, CTX, and CTR antibiotics, which an increased sensitivity was observed.
31. Read the fine print. “Buried in cell phone manuals, cell phone companies specifically instruct us that phones should not be held close to the body. For example, the iPhone 5 manual states “Carry iPhone at least 10mm away from your body to ensure exposure levels remain at or below the as—tested levels. Cases with metal parts may change the RF performance of the device, including its compliance with RF exposure guidelines, in a manner that has not been tested or certified.” The Blackberry Bold states, “keep the BlackBerry device at least 0.59 in. (15 mm) from your body (including the abdomen of pregnant women and the lower abdomen of teenagers) when the BlackBerry device is turned on and connected to the wireless network.
“So what can you do? Straighten up, first of all, says Kenneth Hansraj, M.D., an orthopedic surgeon in Poughkeepsie, New York. And carry device at chest height with head up, chest open and shoulder blades back. Move just your eyes downward. And then, take a break. Your neck is not supposed to stay stuck in one position for a long period. If you’re reading on a tablet or phone, stop every so often to swivel and tilt your head — up and down, then side to side.” – 3 Dumb Things We Do with Smartphones, Good Housekeeping; Twitter: @goodhousemag
The wireless communications industry is rushing to blanket the nation with next-generation networks whose health effects are unknown. Despite studies linking radiation from existing networks to cancer in lab animals, the Federal Communications Commission and state legislators are bowing to industry lobbyists and clearing the way for the new networks.  
There are theoretical considerations as to why the possible risk should be investigated separately in children. Their nervous systems are still developing and, therefore, more vulnerable to factors that may cause cancer. Their heads are smaller than those of adults and consequently have a greater proportional exposure to the field of radiofrequency radiation that is emitted by cell phones. And, children have the potential of accumulating more years of cell phone exposure than adults do.

According to scientists involved in the process, the WHO may decide later this year to reconsider its categorization of the cancer risk posed by cell phones; the WHO itself told The Nation that before making any such decision, it will review the final report of the National Toxicology Program, a US government initiative. The results reported by the NTP in 2016 seem to strengthen the case for increasing the assessment of cell-phone radiation to a “probable” or even a “known” carcinogen. Whereas the WHO’s Interphone study compared the cell-phone usage of people who had contracted cancer with that of people who hadn’t, the NTP study exposed rats and mice to cell-phone radiation and observed whether the animals got sick.47

Add Negative Ions: Exposure to WiFi can result in the build-up of positive ions that can have negative effects on our bodies. We can neutralize this by adding negative ions to our lifestyle, negative ions are highest after a thunderstorm and are present from the energy caused by the crashing waves on the beach. You can also try a negative ion generator.
The aim of this study was to determine the structural changes in the frontal cortex, brainstem and cerebellum in the male rat brain due to electromagnetic wave exposure (900, 1800, 2450 MHz, 1h/day for 2 months). While the histopathological changes in the frontal cortex and brainstem were normal in the control group, there were severe degenerative changes, shrunken cytoplasm and extensively dark pyknotic nuclei in the EMR groups. Biochemical analysis demonstrated that the Total Antioxidative Capacity level was significantly decreased in the EMR groups and also Total Oxidative Capacity and Oxidative Stress Index levels were significantly increased in the frontal cortex, brainstem and cerebellum. Researchers concluded that EMR causes structural changes in the frontal cortex, brainstem and cerebellum and impairs the oxidative stress and inflammatory cytokine system. This deterioration can cause to disease including loss of these areas function and cancer development.
Turkish Telecommunication and Information Technology Agency declared that the daily usage of internet is nearly 6 hours in Turkey [15]. Therefore, according to us, Wi-Fi usage needs to get more attention than cell phone usage due to its higher frequency ranges and longer exposure times [16]. Even though there are some studies performed on the effects of  RF-EMR and cell phones on male fertility, there is not so much scientific data about the association between Wi-Fi internet usage and male fertility [17]. Unlike other RF-EMR sources, devices such as laptops and tablets usually stay near the reproductive organs.

In September 2014, Californian oncologists reported four similar case histories of young women who had developed breast cancer in precisely the areas where they normally carried their smartphones. What shocked the doctors was that these women were aged 21 to 39 and had no family history or other risk factors relating to cancer. All their cancers “had striking similarity, all tumours were hormone positive… (with) an extensive intraductal component and… near-identical morphology.” (CaseRepMed., 2013).