Did you know you're more likely to get skin cancer from pool chlorine and sunblock than the sun? that is of course assuming you're not albino, and/or suntanning as a hobby for 8 hours a freakin day.
"After 40 minutes of swimming, people in a study showed a rise in markers of DNA damage that can lead to cancer."
Chlorine in swimming pools can strip the coating off titanium dioxide nanoparticles in sunscreens that protect against UV radiation, leaving them able to react with water and form compounds that can contribute to skin damage and cancer. The nanoparticles, which protect against harmful UV rays, are coated so they remain stable in sunlight. But a new study for the first time shows that the protective coating can degrade to form free radicals. Free radicals are known to damage DNA, causing aging and potentially leading to cancer. Whether there is a human health effect from exposure to these compounds is unknown. But the study raises the question of whether sunscreens meant to protect people from sunlight are creating another risk that also can harm skin. 
Lovely huh? the sun has been there throughout all human history and what do you know people weren't dropping like flies from cancer like they are now a days. i mean if you stand out in the sun ALL DAY EVERYDAY yeah you're asking for it and you're the exception. but people don't get enough sun, and if they do they burn its because of their lack of sun exposure, or they use sunscreen and see above direct quote.
the whole point of why sunlight is good and why we "tan" is the sun's effect on the melanin pigment in our skin, that melanin absorbed sunlight, and creates vitamin D which is actually a hormone not a vitamin.
Vitamin: "A vitamin is an organic compound required by an organism as a vital nutrient in limited amounts"
Hormone: "is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells"
Although vitamin D is commonly called a vitamin, it is not actually an essential dietary vitamin in the strict sense, as it can be synthesized in adequate amounts by most mammals exposed to sunlight (cats and dogs cannot synthesize vitamin D and must receive it in their diet). An organic chemical compound (or related set of compounds) is only scientifically called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from their diet. 
Sunscreen absorbs ultraviolet light and prevents it from reaching the skin. It has been reported that sunscreen with a sun protection factor (SPF) of 8 based on the UVB spectrum can decrease vitamin D synthetic capacity by 95 percent, whereas sunscreen with an SPF of 15 can reduce synthetic capacity by 98 percent 
vitamin D deficiency is related to a plethora of bone problems such as rickets and osteoporosis as well as some cancers, vitamin D is a cancer killer folks, bask in the rays of its awesomeness.