Breasts are a part of the human anatomy in both sexes. For females, due to the complexity in particulars of composition unique to the feminine sex, there are more factors that affect the breast. Whereas women are concerned, breasts develop amid the stages of puberty through sexually based hormones, and, in particular, the hormone known as estrogen. In rare instances, an abnormality referred to as gynecomastia, creates an enlargement in the breasts of men. Amongst extreme instances, for those men who undergo a sex change, the gynecomastia effect is replicated in a form of hormonal therapy to replenish or establish the development of breasts in the physical transformation from male to female.
The factors that affect the breast of women during the stage of development referred to as Tanner, include the phase when each breast folds downward upon and over the wall of the chest. Throughout a woman's development of breasts, each breast will grow at a slightly different rate of maturity, and, in the majority of instances, it is the left breast that will be marginally be the largest of the pair. Although a rarity, some women have experienced an abnormality in the development of their respective breasts, in either that there will be a distinct differential in the sizes of each breast, or, a total lack of any development in one or both breasts.
Within abnormalities of breast development, amid a woman's puberty, there are a considerable number of medically based conditions that can hamper the growth of breasts during this early stage of womanhood. One of the more significant adverse factors that affect the breast development are classified as virginal breast hypertrophy, whereas the breasts grow at an excessive rate, and, in certain instances, will continue in the pattern of such excess beyond what is considered normal age ranges of puberty. Another adversity, in direct opposition, among factors that affect the breast, is labeled hypoplasia. This abnormality is in the event of being that one or both breasts are completely void of any developing growth.
Although more notable during a young woman's stages of puberty, the adipose tissue, which makes up the greatest amount of the composition of the breasts, during a woman's entire lifetime, alters throughout the passage of time. Factors that affect the breast, in regards to this particular mass of tissue are changes in a woman's body weight, whether it is an increase or decrease, resulting in changes to the size of the breasts. Such affects, particularly if the variance in weight takes places over a short period of time, is evident in notable stretch marks on the surface skin layers of the breasts. As a woman matures, throughout her life, natural and unavoidable sagging of the breasts will occur, due to the elongation of the ligaments, based upon the weight of the breasts combined with the natures force of gravity.
Menstruation cycles has its factors that affect the breast size of the woman, due to what is termed as premenstrual retention of water. Women that practice birth control through the usage of an oral contraceptive will commonly experience increased size in their breasts.
Pregnancy, for a woman, brings about factors that affect the breast. The breasts, due to the lactation process, increase in their volume or size, as well as a degree of enhanced firmness. Such process is due to what is referred to as the mammary gland's hypertrophy, in correlation to prolactin, which is a natural hormone within the woman's body chemistry. Nipple sizes of the breasts are visually more pronounced, as the areola may darken somewhat. These alternations in the breasts can be a continuation throughout breastfeeding. Following the combination of the natural processes of lactation and breastfeeding, the size of the woman's breasts will generally return to their pre-pregnant state, with the unfortunate aspect of the possibility of a degree of sagging, along with evident stretch marks.
Breastfeeding is among the factors that affect the breast by the mammary glands stimulation, in their natural function, to produce breast milk. Such process is what is referred to as lactation, whereas milk is produced for the benefit of the newborn infant. A relevant source of a theory claims that the orb-like shape of the woman's breasts, through evolution, prevents risks of suffocation for the infant as it nurses. An amazing fact, breasts of both sexes – female and male alike – possess mammary glands, though such glands in males do not develop. Another biological benefit to the orb-like shape of the woman's breasts is that such natural symmetry minimizing heat loss in regards to the temperature of the breast milk produced for the feeding infant.
Galactorrhea, excessive stresses of a physical nature, or disorders brought about through endocrine are factors that affect the breast of women, which are not related at all to pregnancy, whereas lactation of milk occurs. In the rarest of instances, where the breasts of men are concerned, in regards to this extreme abnormality of production of milk presents itself, such a condition is termed male lactation.