Why do women wear bras? The answers are varied: aesthetics, to reduce the risk of sagging breasts later in life, and to reduce sports injuries. Because the standard of breast beauty has evolved through history: high, round, and preferably with deep cleavage. Bras designed specifically for breasts were born in the early 20th century, but now they have become a must-have for women in civilized society. When it comes to bras, it is important to briefly address the basic issue of breasts: who owns them? Does it belong to the baby who must rely on breast milk or milk substitutes? Or does it belong to the man or woman who caresses it? Does it belong to the artist who portrays the female body, or to the authority who constantly caters to the new demands of the market, and who determines exclusively the beauty of breast size? Does it belong to the bra makers who sell girls’ bras, support bras and magic bras to young girls, mature women and women with small breasts, or does it belong to the religious and defenders who constantly demand that women cover their breasts with modesty? Does it belong to the law that defends the arrest of “empty women” or does it belong to the physicians who have the right to decide how often women should have mammograms, when to have biopsies and mastectomies? Does it belong to the plastic surgeon who cosmetically augments a woman’s breasts, or does it belong to the pornographer who pays for it, exposes it, and then uses it to degrade and harm women? The breast is a part of a woman’s body, but does it belong to her? Is a bra really essential? Can it really prevent sagging breasts? We all know that after the fracture is fixed in a cast, the local muscles must have atrophied to varying degrees after the cast is removed and need to be exercised to recover their original shape. Then the breast is attached to the pectoralis major muscle, with a bra or corset to fix the breast, the pectoralis major muscle also does not need to support the breast, making the chest muscles, breast and surface skin are in a static state, which is not conducive to the strength of these tissues. The earlier a girl wears a bra, the less opportunity she has to develop her own breast support system. So, when women who have been wearing bras for a long time take them off, the breasts without their own support system tend to sag. 2003, there was a study in Belgium on female athletes aged 18-25 who did not wear bras. The female athletes were involved in sports such as gymnastics, running and swimming. For the first six weeks, most of these women complained of discomfort when exercising, but the study found that their skin became tighter. The discomfort disappeared after about six months, and the athletes felt more comfortable and more comfortable exercising. Measurements a year later found that their breasts were firmer and more uplifted. French sports medicine doctors have been studying the effects of bras on women for 16 years and have also concluded that medically, physiologically, and anatomically, the rejection of gravity does not do any good for the breasts; rather, wearing a bra makes the breasts sag more, and women wear bras for comfort in a social sense more often than not. Many cases have been reported of phlebitis and lymphangitis of the chest wall associated with the wearing of overly tight bras, and it is unclear whether there is a relationship with the increased incidence of breast cancer. Human beings have a history of millions of years of development and have flourished from ancient times to the present. In terms of evolutionary development, bras are not necessarily related to human beings. In terms of the incidence of breast cancer and non-lactating mastitis, the incidence has increased 5-6 times in the last hundred years. In addition to human lifestyle, environmental pollution, genetic inheritance and other factors, improper bra wearing is also to blame. Therefore I suggest that women, except on necessary occasions, try to relax their chest as much as possible, so that also the breasts can breathe freely.