PIP: This article briefly describes the reasons for breast feeding exclusively during the first three months of life. Wet nursing was initially an appropriate alternative in cases of maternal death, abandonment, or severe mental or physical illness. The well-to-do have used wet-nurses since the 1st century as part of a popular norm. The option for alternative feeding increased during the 18th century when middle class women sent their infants to be wet-nursed. A safer means of producing infant milk formula from cow's milk was developed. Well-to-do women were the first to be able to afford the high cost of infant formula. Bottle-feeding with formula became a symbol of affluence and became widespread. Breast feeding became associated with inferiority. Women's breasts were exploited as sex symbols, and mothers experienced shame associated with breast feeding. The shift back to breast milk among the well-to-do was a recognition of the nutritional merits of breast milk. Infant formula manufacturers were never able to produce an exact substitute for breast milk. Breast milk provides complete nutrition without a need for water supplements. Breast milk is easier to digest, produces less waste, does not overwork the kidneys, cleans and strengthens the gastrointestinal tract, and has disease fighting potential. Colostrum during the first days of birth provides natural immunity to disease. Breast feeding promotes healthy skin and less incidence of respiratory, diarrheal, and constipating illnesses. Breast milk substitutes cannot produce anti-bodies to disease as breast feeding mothers can during illness. Breast milk does not have an expiration date due to contamination. Suckling by infants helps the development of the jaws. The nursing process encourages rotation of the infant's eyes and reinforces the maternal-infant bond. Babies who self-wean demonstrate independence and emotional security in later life.