I had level 4 Melanoma 30 years ago. It was caused by my hormones (as determined by my ob/gyn and surgeon - I was 8 months pregnant when diagnosed). So the sun alone is not the sole cause of melanoma. Overuse of anything is not good for us. I love the sun and do NOT use sunscreens at all, not even here in Phoenix (ok I do seek the shade from 9 am until 6 pm....) but I refuse to use sunblocks, I want as much natural Vit D as I can get over the synthetic kind. If you expose part of your skin (hand, foot, etc) to the sun for 10 to 20 minutes per day (not even all at once) you can get your daily dose of Vit D (or so they say).