In clinical practice, I often encounter breast cancer patients and their family members asking: Should we have a normal sex life after having breast disease or not? What’s more, a very good friend from a university work in Yantai, whose wife got breast cancer 5 years ago at the age of 38, has a good quality of survival, but by chance told me that she has not had sex once since the onset of the disease, worrying that sex promotes the development of breast cancer. I would like to elaborate here that sex has no negative effect on breast cancer. The effect of sex on breast has long been medically proven, and in fact, the breast itself is an important sexual organ. Breast diseases and sexual life are closely related, and sexual repression in women can increase the chance of developing lobular hyperplasia and breast tumors. During sex, the first signal of female sexual excitement is sent from the breast under the stimulation of sex hormones – the breast tissue is rich in sex hormone receptors and the nipple is erected due to muscle contraction, so the nipple is bigger and harder than usual during sexual excitement. In addition, there is trembling in the breasts during orgasm, which promotes blood flow to the breasts. And because of the expansion of blood vessels in the breast, blood flow increases, the skin of the breast will be red, the volume of the breast can be increased by 20% to 25% compared to before sex. After orgasm, the breasts gradually return to their original form – the erect nipples collapse and soften, the reddened breast skin fades to a normal color, and the breast volume shrinks to a normal state. Regular sexual life is of great importance for the physiological activity and function of the breast. With regular sexual excitement, the structure and function of the breast are well “exercised” – sexual excitement obviously activates the blood supply to the breast, thus allowing the physiological enlargement and rejuvenation of the breast to proceed smoothly. If the sexual life is not harmonious, such as orgasm is not well aroused, then the engorgement of the breasts will be slow to subside, and there can be breast swelling and chest discomfort. In fact, this is due to breast bruising, which is also one of the causes of breast enlargement – frequent bruising will inevitably bring about structural disorders of the mammary glands. Similarly, if there is a long-term lack of sex, the breasts, as sexual organs, are not stimulated by sexual excitement for a long time, and the structure and function of the breasts are not well “exercised”, the physiological enlargement and rejuvenation of the breasts can not be carried out smoothly, thus increasing the incidence of mastopexy. This has been confirmed by epidemiological data. A number of population surveys on the incidence of mastocytosis have shown that the incidence is higher in late marriages, divorces, widowhood, lifelong unmarriage, and marital discord. There is also evidence that these are also high risk factors for the development of breast cancer. Domestic surveys show that 86% of women with lobular hyperplasia have never reached orgasm during sex. Healthy and regular sexual activity plays an irreplaceable role in enhancing the relationship between husband and wife, helping the wife to restore female dignity, mobilizing confidence to overcome the disease and creating a harmonious family environment. In addition, patients who receive breast-conserving treatment and first-stage breast reconstruction after breast cancer surgery have no worries about their physical appearance and do not have to worry about or psychologically resist the normal functioning of their physiology.