Family history of hereditary breast cancer can be in two forms: one is that the mother has breast cancer and the daughter also has breast cancer, the age of onset is young, often occurs before menopause, and is mostly bilateral; the other is that the mother has not had breast cancer, but in a family, at least two sisters have breast cancer, the incidence of breast cancer in such families is 2-3 times higher than that in families without family history. The risk of breast cancer in such families is 2-3 times higher than that in families without family history, and it occurs mostly after menopause, often unilaterally; 2. Menstrual factors: if the age of menarche is earlier than 12 years old, the risk of breast cancer is 2.2 times greater than that of menarche at 17 years old; if menopause is later than 55 years old, the risk of breast cancer is 1 times higher than that of menopause after 45 years old. The risk of breast cancer can be reduced by half if both ovaries are removed before the age of 45. The early age of menarche and late age of menopause often make breast cancer more likely to occur due to the prolonged effect of estrogen in the breast tissue. Repeated abortion, or multiple abortions before the age of 18, may cause breast diseases and increase the risk of breast cancer. After a normal birth and breastfeeding, the breast tissue is well developed and the chance of developing tumor is reduced. However, women who have their first childbirth have a high chance of breast cancer, and those who have their first childbirth at the age of 35 or above have a higher chance of breast cancer than those who do not have children. Breastfeeding factor: The effect of postpartum breastfeeding on the occurrence of breast cancer is not completely clear, but recent studies have concluded that the longer the total duration of breastfeeding, the lower the risk of breast cancer. Breastfeeding is one of the best natural means to prevent breast cancer, and it can reduce the risk of breast cancer by 20% to 30%. 5. Poor quality of sex life: Breast diseases and sex life are closely related, and sexual repression in women can increase the incidence of lobular hyperplasia and breast tumors. Domestic survey shows that 86% of women with lobular hyperplasia have never reached orgasm during sex; the older the age of first marriage, the higher the incidence of breast cancer. 6. Depression: Among single women, ladies left behind, PR girls, retired female workers and some secondary school teachers, more suffer from breast diseases and have a high incidence of breast cancer. As these women are prone to depression, such as tension and anxiety, loneliness and depression, sadness and sorrow, bitterness and disappointment, impatience and irritation, the body’s life rhythm will be disturbed and the neuroendocrine system will be dysfunctional, which will lead to the imbalance of the internal environment and the decrease of immunity, so that the thymus gland will produce and release less thymosin, and the lymphocytes and macrophages will be less able to monitor and phagocytose mutated cells in the body. The ability of lymphocytes and macrophages to monitor and phagocytose mutated cells in the body is reduced, and cancer is likely to occur. 7. Excessive obesity: obesity is closely related to breast cancer. Girls who are obese are prone to early sexual maturity, which will lay the foundation for breast cancer in the future. The incidence of breast cancer in obese people is 3.45 times higher than that of non-obese people, because excess fat accumulation increases the production of estrogen, and excess estrogen is lipidated and stored in the fatty tissue and constantly released into the bloodstream, which stimulates the breast tissue and, over time, easily causes breast cancer. In addition, most of the obese people have hypercholesterolemia and hyperinsulinemia. After the cholesterol in the body is elevated, the cholesterol content in the cell membrane of lymphocytes and macrophages is elevated, which inhibits the immune function. 8, bad habits: to smoke, alcohol as “fashionable”, to nightclubs, dance halls, all-night immersion in the lights, like to eat fried food and a variety of pastry sweets, but never to rough food, vegetables; celibacy, or after 30 years of age before marriage and childbirth, the child does not want to breastfeed; also some women wear bras 9.X-ray exposure: Epidemiological studies have found that long-term exposure to X-rays, such as the increased incidence of breast cancer among survivors of the atomic bombings in Hiroshima and Nagasaki, Japan, so it is important to prevent excessive exposure to radiation, especially in young unmarried women. 10. Breast diseases or benign tumors: It has been found that the chance of breast cancer in people with a history of breast fibroadenoma is 1 to 2 times higher than normal people.