This is extremely controversial but we can’t ignore that plenty of animal models indicate that exposure to electromagnetic radiation increases the risk of tumor development. While human studies are rare, reports and case studies abound. One such case involves a young 21-year-old woman who developed breast cancer. What makes this case unique was that her family did not have a predisposition to breast cancer… and she developed the tumor right on the spot she carried her cell phone in her bra. 
42. Limit your child’s time on the phone. There’s much discussion about how much screen time is good for kids and teens today, and today’s wireless devices provide access to all the games, chatting features, web browsers, media, and apps they could possibly consume in a lifetime. Setting clear limits on smartphone usage will help you keep screen time within reasonable limits. “Half an hour of screen time is recommended for children 4-5 years old; an hour for ages 5-10; and two hours for high school aged kids.” – Melanie Medina, Growing up Digital – Cell Phone Safety for Kids, Identity Force; Twitter: @IdentityForce
The microwave irradiation was performed at bands corresponding to mobile devices (GSM) using a modified AP5200 generator (D-LINK, China), operating in four bands (860–910 MHz frequency range, Pout 29 dBm), and to wireless router (WLAN) using a D-LINK wireless router 802.11 g/2.4 GHz (2.412–2.48 GHz frequency range, Pout 19 dBm). In the irradiation chamber there is one stick antenna placed in the center of the ceiling. The exposure levels where chosen in agreement with the microwave irradiation levels measured in open space for heavily used GSM networks (100 mW/m2) and for indoor WLAN (70 mW/m2) communication protocols.
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.
The present study aimed to investigate the effects of chronic low-intensity microwave exposure (900, 1800 or 2450 MHz for 180 days) on cognitive function, heat shock protein 70 (HSP70), and DNA damage in the rat brain. The results showed declined cognitive function, elevated HSP70 level, and DNA damage in the brain of microwave-exposed animals. The results indicated that, chronic low-intensity microwave exposure in the frequency range of 900 to 2450 MHz may cause hazardous effects on the brain.
This overview shows that effects of 2.45 GHz radiation have been found by different research teams, repeatedly, in different study objects, and at different exposure levels. A broad spectrum of issues has been investigated such as the effects of 2.45 GHz radiation emitted by a Wi-Fi router on the release of mercury from amalgam fillings. The mercury levels were significantly increased (Paknahad et al. 2016).