Ultraviolet rays have many harmful effects. If you do not believe that ultraviolet light causes aging of the skin, then compare the skin on the back of your hands to the skin on your inner thigh or buttocks. As we grow older we develop brown marks, wrinkles and thinning of the skin on the areas of the skin which are exposed to sunlight. These changes can most readily be seen in people over fifty years of age. These same areas are also the sites of skin cancer.
Most skin cancers occur on the face.
Skin cancer almost never occurs on the buttocks, under the arms or on the inner thighs. The skin has several defense systems to help protect it from ultraviolet rays. The most important of these is the pigment or color of the skin. The skin is made of building blocks called cells. One type of skin cell, the melanocyte, produces a chemical called melanin.