Moles can be present at birth, develop during childhood, or appear over time as a result of sun exposure or genetics. While moles are typically harmless, in rare cases they can become cancerous. That’s why it’s so important to monitor moles—especially those that appear suddenly in adulthood, or have an unusual appearance—and to seek a professional examination. Even when benign, moles can affect our comfort, appearance, and self-esteem, and many patients decide to have them removed.