evidence: Nov. 28, 2023 -- The "sunscreen paradox" has confounded doctors of late: As more and more people use sunscreen, rates of melanoma and other skin cancers are going up. [...] Why is this happening? A new study from McGill University in Montreal might have solved some of the mystery: Many people may think sunscreen gives them free rein to tan or stay out in the sun as long as they want to. [...] You Don’t Wear Sunscreen Indoors "There are unexpected ways in which one may get sun exposure without realizing it," Sivendran said. "For example, the sun’s rays penetrate through windows, so sitting near a window for a prolonged period can increase skin cancer risk. It is important to wear sunscreen indoors to reduce this."