According to the American Academy of Dermatology, the majority of moles appear during the first two decades of a person's life, while about one in every 100 babies is born with moles. Acquired moles are a form of benign neoplasm, while congenital moles, or congenital nevi, are considered a minor malformation or hamartoma and may be at a higher risk for melanoma.A mole can be either subdermal (under the skin) or a pigmented growth on the skin, formed mostly of a type of cell known as a melanocyte. According to the South Asian Public Health Association, moles on the bottom of the foot are significantly more prevalent among Asians than among caucaison people. The high concentration of the body's pigmenting agent, melanin, is responsible for their dark color. Moles are a member of the family of skin lesions known as nevi.