Moles, medically known as nevi (singular: nevus), are the most common type of skin growth. They are caused by a cluster of pigmented cells called melanocytes, and can vary anywhere from pink to tan to brown and even black. They can be flat, raised, dark, and light and can often grow hair. Moles can grow anywhere on the body, including the genitalia, scalp, fingers, toes, legs, back, and more. Some moles appear at birth or early infancy and grow with you as the years go by. Once you reach mature adulthood, it’s less common to develop new moles and any new moles should be regarded with greater attentiveness. New moles after the age of 50 are very uncommon, although the body makes lots of other fun stuff and several mole imitators. Although most moles are non-cancerous it is important to get them checked if they are growing rapidly (discernable diameter change over a 6 month period is usually too fast), changing colors, fading away, becoming ragged at the edges, asymmetric, or starting to ulcerate and bleed.