There's still a lot we don't know about cell phone radio waves and the damage they cause, as research data is inconsistent. But as a safety precaution its usually recommended to limit phone exposure to your head for just in case reasons.
Radio frequency can cause heating similar to what microwaves do. Phones close to any body part does cause heating in that area, causing human tissues to heat, the only concern is if its close to the body. It may or may not cause cancer and tumors.
It's non-ionizing radiation, and you heat your body faster with more cell damage by sticking your cold hands on the car vents on max in the middle of winter xD But yeah, every -credible- source has found no reliable evidence to show that it damages or causes cancer, but they suggest moderation anyway -just in case-.
Edit: https://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/cell-phones-fact-sheet#q5
sources for each research are listed halfway down'ish
In 2015 the European Commission Scientific Committee on Emerging and Newly Identified Health Risks concluded that, overall, the epidemiologic studies on cell phone radiofrequency electromagnetic radiation exposure do not show an increased risk of brain tumors or of other cancers of the head and neck region (1). The Committee also stated that epidemiologic studies do not indicate increased risk for other malignant diseases, including childhood cancer (1).
Last edited by SonyUSA,