They are problematic. The SPF rating in sunscreen refers only to the UVB rays that cause sunburn but not the UVA rays that cause skin cancer. Many users may be absorbing far more UVA radiation than they are aware of.

Many sunscreen ingredients have hormone disruptors that can be detected in users' blood and breast milk. The worst, oxybenzone, is killing coral reefs by mutating the DNA of corals. It has been banned in Hawaii.

Cancer Council of Australia states that ultraviolet radiation from the sun is beneficial to human health but that a balance is required between excessive sun exposure and enough sun exposure to maintain adequate vitamin D levels and gain the many other benefits sunlight has to offer.

New Zealand signed on to similar recommendations, and the British Association of Dermatologists stated that people should enjoy the sun safely while taking care not to burn.

Sunlight triggers the release of serotonin and endorphins. It reduces the risk of prostate, breast, colorectal, and pancreatic cancers. It reduces inflammation and decreases autoimmune responses.

Sun rays do increase the rate of skin cancer, but for every one person that dies of skin cancer, over 100 die from cardiovascular disease.

• People who get carcinomas tend to be healthy people that get plenty of sunlight. Carcinomas are seldom fatal.
• Melanoma, the deadly type of skin cancer, accounts for 1 - 3 % of new skin cancers. The most significant cause of melanomas is sporadic sunburn.

A dermatologist discovered our skin uses sunlight to make nitric oxide, a molecule in the body that dilates blood vessels and lowers blood pressure.

He exposed volunteers to the equivalent of 30 minutes of summer sunlight without sunscreen. The result? The nitric oxide levels in the volunteers went up, and their blood pressure lowered. Because of the connection of high blood pressure to heart disease and strokes, this discovery can prevent millions of deaths globally.