One of the convenient features of having a smartphone is to quickly access email or social media accounts with just a tap of a finger. However, this also means that you are always connected to accounts that may contain sensitive information. Consider logging out of certain accounts if you can so that others can’t access those accounts if they are using your phone. Keep in mind that depending on the type of phone you have, you might not be able to log out of some accounts, such as email accounts, but may have to remove the entire account from your phone. In this case, make your decision based on your own privacy and safety risk. While it may be inconvenient to access the account through the browser instead, it may be safer.
The aim of this study was to investigate long-term effects of 2.4 GHz radiofrequency radiation (24 h/day for 1 year) emitted from a Wireless Fidelity (Wi-Fi) system on the testes of male rats. Results showed that sperm head defects increased in the exposure group (p < 0.05) while weight of the epididymis and seminal vesicles, seminiferous tubules diameter and tunica albuginea thickness were decreased in the exposure group (p < 0.01, p < 0.001, p < 0.0001). However, other alterations of other parameters were not found significant (p > 0.05). We suggest Wi-Fi users to avoid long-term exposure of RF emissions from Wi-Fi equipment.
When it comes to cell phones, scientists have looked at findings from animal research and cells in test tubes exposed to RF radiation in a lab, as well as observational studies in humans. These human studies have tried to see whether heavy users of cell phones have higher rates of brain cancers and other health problems compared with people who use cell phones less often.
The Federal Communications Commission (FCC),  US Government Accountability Office (GAO),  and the US Food and Drug Administration (FDA),  have all concluded that there is no evidence in the scientific literature proving that cell phones cause brain tumors or other health problems. According to the FDA, "attempts to replicate and confirm the few studies that did show a connection [between cell phone radiation and head tumors] have failed." 
Disclaimer: The entire contents of this website are based upon the opinions of Dr. Mercola, unless otherwise noted. Individual articles are based upon the opinions of the respective author, who retains copyright as marked. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the research and experience of Dr. Mercola and his community. Dr. Mercola encourages you to make your own health care decisions based upon your research and in partnership with a qualified health care professional. If you are pregnant, nursing, taking medication, or have a medical condition, consult your health care professional before using products based on this content.
I really want to caution you to be careful of any "expert" or EMF blogger recommending anti-radiation filtering cases, stickers that attach to the phone or necklaces to "ward off" EMF. I get it, when I first realized 25 years ago that I was sensitive to electromagnetic energy and then later, when I understood that without a doubt, man made electromagnetic radiation has a biological effect on my body, I wanted an easy fix. I tried the shielding materials and cases and I just did not feel any better. Then I bought meters to see if the energy changed and I actually noticed what the California Department of Health now says and it's what the FTC and FCC post warnings about: "Some shielding materials can make exposures worse". So please, be careful and read on for what you can do to avoid electromagnetic radiation exposure.
If you use a USB Wi-Fi adapter (for PCs that don’t have a built in wireless network interface card) use it on a USB extension cable (10 feet or more). The same goes if you use a 3G or 4G USB internet stick, or dongle, to connect to the Internet while you’re traveling. A USB extension cable will significantly reduce your exposure. Tip: the further the USB internet stick is from you when you’re surfing the Web, the less you will be exposed. Buy a USB extension that’s a good 10 to 15 feet long.
Studies by five independent research groups regarding cell phones and brain tumors have revealed significantly increased risks of a benign tumour of the cranial nerve supplying the ear. This grows slowly and must be removed in a major operation that can result in permanent facial paralysis. Other risks found were cancer of the glial cells (including neurons) of the nervous system and cancer of the meninges, the membrane covering the brain and spinal cord.