Check out this post from WSJ.com: Health Blog:
Contrary to the earlier paper’s assumptions, Dr. Godar et al. found that children aren’t outdoors more than adults: “Surprisingly, it is adults over the age of 40, i.e. 41–59 and 60+ years, especially men, who get the highest UV doses.” They added that a rise in incidence of skin cancer “may have occurred because adults assumed that they no longer had to worry about getting too much UV exposure because they were told that most of the damage was done before 19 years of age.
(from: A Summer Myth Debunked)