From A Dermatologist Who’s Not Afraid to Sit on the Beach:
Other dermatologists may worry about getting melanoma from exposure to ultraviolet rays. But Dr. Ackerman, 67, a renowned expert in the field and the emeritus director of the Ackerman Academy of Dermatopathology in New York, said the link between melanoma and sun exposure was ‘not proven.’
[...]
For example, it is commonly assumed that painful or blistering sunburns early in life set the stage for the skin cancer later on. But while some studies show a small association, Dr. Ackerman says, others show none.
[...]
Common wisdom also has it that sunscreens protect against melanoma. But Dr. Ackerman points to a recent editorial in the journal Archives of Dermatology concluding that there was no evidence to support that idea.
There is a link between sun exposure and skin damage — and even to other skin cancers (besides melanoma) though:
Stay out of the sun, Dr. Ackerman advises, but do it to avoid premature aging of the skin. If you are very fair, avoiding sunlight will also help prevent squamous cell carcinoma, a less dangerous cancer. But it would be a mistake, he says, to assume that avoiding sunlight or using sunscreens will offer protection from melanoma.
(Hat tip to Mercola’s Health Blog.)