More sun exposure may be good for some people

Melanoma is triggered by UVA (the long UV wavelengths) and visible light. Vitamin-D production in the body, on the other hand, is triggered by UVB (the short UV wavelengths at the earth's surface). "So perhaps we should redesign sunscreens so they don't screen out as much UVB while still protecting us from the melanoma-inducing UVA and visible light," Setlow says.