A supernumerary nipple (also known as a third nipple, triple nipple, accessory nipple, polythelia or the related condition: polymastia) is an additional nipple occurring in mammals, including humans. Often mistaken for moles, supernumerary nipples are diagnosed at a rate of 1 in 18 humans. "Cancer hope over breast gene find", BBC, 1 September 2005; references the rate of extra nipples appearing in humans. Presentation The nipples appear along the two vertical "milk lines", which start in the ar… (More on Polythelia)