How does breastmilk develop?

The breasts have what is called mammary glands in them. When puberty begins the breasts normally enlarge from the hormone, (O)estrogen. The breasts have a series of tubes that radiate from the common center, ie' the nipple, where a number of slight nodules on the areola are formed by the milk glands under the surface of the skin. The tubes, ranging from 15 to 20 extend from the lobes of the breast and open at the nipple. When a breast is inactive, no pregnancy, is consists of mainly connective tissue and fat. During pregnancy, or attempting to induce lactation, the breasts enlarge and the mammary glands become active and when sufficient levels of the hormone required to trigger milk production, is present, milk is released into tiny ducts where stimulation of the nipple and areola may cause the milk to be ejected from the nipple. Additionally, Note, that a woman does not have to be pregnant, or have had a child for this to happen, it may also happen due to the effects of a hormone imbalance which may be unexplainable, caused by a pituitary tumor, or caused by regular nipple stimulation. Some women have started lactating by heavy nipple play alone.