> No, because they have a demonstrable mechanism from pre-established science: UV radiation damages DNA, which causes cancer. Their product absorbs or scatters

> No, because they have a demonstrable mechanism from pre-established science: UV radiation damages DNA, which causes cancer. Their product absorbs or scatters UV radiation. As mentioned in article, but also some general knowledge in physics is that interaction of radiation with the matter is probabilistic. It is not like every quantum of UV radiation will always damage DNA, which always result in cancer. There's some "conversion funnel" that depends on a number of parameters, and the actual probability of cancer in the end could indeed be lower than probability of the negative consequences of low sun exposure. Even if physical mechanism of diseases is established, it does not mean we should always avoid the risk by disabling it by some expensive means. Sometimes it is low enough to accept it or mitigate (e.g. by efficient cancer treatment).