The variation in the size of "normal breasts" may be the greatest single biological variant among women. When breasts develop to a volume of more than a liter or so, they become an encumbrance for which partial amputation is the only treatment. Although correlation of breast size with general body weight is common, there are conditions of progressive breast hypertrophy, even in patients who are not generally obese, the causes of which are not known. This can result in breasts so large that the nipples migrate below the waist and the weight may be too great to recarried. Breast reduction can now be accomplished in such a way that a reasonably sized and shaped breast can be achieved. Usually, nipple sensation and lactation remain intact. Very large breasts, with a super sternal notch to nipple distance greater than 40 centimeters and measuring liters in volume, may require nipple removal and replacement as a skin graft, in which case sensation and lactation are not likely.