Sunscreens can get a bad rap from promoters of alternative medicine, often returning to the well used warnings about the dreaded Toxins. While being aware of what you apply to your skin is a good idea the scaremongering employed by these groups is almost certainly counter productive in terms of reducing cancer risk in those exposed to the harmful effects of the sun. To assert that the application of sunscreen itself actually causes cancer is to both willfully misinterpret the medical literature and engender ill founded paranoia in those that are susceptible to such tactics.
This is not to say that sunscreens are universally good or are a magic bullet for cancer prevention. There have been studies that found a positive correlation of cancer with screen use, however this is likely due to an over-optimistic attitude towards the capabilities of the screens as well as the fact that almost by definition people who use sunscreens tend to spend more time in the sun. Even so, my own opinion that the nuclear furnace that dominates our sky is over rated, is one that even today should probably not be encouraged.
With regards to use of sunscreens as well as outdoor activities in general it should be realised that a responsible attitude towards sun exposure is prudent, cover up and limit sun exposure when able and reapply sunscreen often. It is generally recognized that the light from our closest star is beneficial to our health in many ways but as with anything else moderation is the key and an overdose can have fatal consequences.
http://www.worldimage.com/blog/archives/000027_sunscreen_dangers.html some sunscreen bashing, luckily they sell their own.
http://www.lyricscrawler.com/song/3953.html -The “Sunscreen song” just because.