In most cases, the human body’s breasts themselves have a difference in size, which is normal. This is normal. This is mainly due to the two sides of the breast in puberty growth and development process, to receive the hormone will not be exactly the same there will be a slight difference in the size of the breasts will also cause a slight difference, this difference as long as it is not too obvious is normal, do not need to worry about it too much. If the breasts appear to be very obvious one big and one small, it is necessary to consider the growth process of abnormal hormone reaction, and recommend the hospital for examination and treatment. In addition, if some patients suddenly develop a large or small breast size after the developmental period, accompanied by symptoms such as inconsistent breast tenderness or the formation of lumps inside the breasts, it is necessary to pay attention to whether it is due to breast diseases, and should go to the breast surgery department in time for consultation and treatment.