Sunscreens alone may not be enough. But covering up with a T-shirt may do the trick, suggests a study of more than 1,800 children. The authors recommend using both sunscreen and cover-ups for the best defense. An 85% polyester, short-sleeved T-shirt provides about the same protection against sunlight as a sunscreen with a sun protection factor (SPF) of 5 to 10. Why worry about moles at all? Because they can raise the risk of skin cancer.

American Journal of Epidemiology