Early age at menarche and late age at menopause, nulliparity, and late age at first pregnancy have been associated with an increased risk of BC. In contrast, parity and the increase in time breastfeeding, particularly during the first child have been associated with a decreased risk. The hypothesis that ovarian function, through their hormones, plays an important role in the etiology of breast cancer has been supported by various studies for a long time. Although most of the risk factors associated with reproductive characteristics are difficult to modify, to increase the breastfeeding time and to avoid exposure to known carcinogens during periods of development of the mammary gland are good strategies to reduce the risk of this disease.