Breast development is one of the first visible signs of the onset of puberty in girls. It usually begins between the ages of eight and thirteen, shortly before the growth spurt.

Female breast development is measured in stages based on contour (shape), not size. There are five distinct stages of breast development, called Tanner stages: prepubertal—no signs of breast development; early breast budding; elevation of the breast and areola (the pigmented ring surrounding the nipple); projection of the areola and nipple above the breast itself; mature breasts—areola flattened to the level of the breast with only the nipple projecting.

Breast size is not related to sexuality, femininity, or fertility. Nonsurgical means of increasing the size of small breasts (such as creams, pumps, and massage techniques) do not work. Hormonal medications, including oral contraceptives, sometimes cause an increase in breast tissue. Exercise can increase the...