There are many reasons why men have big breasts, which can be divided into the following categories: 1, puberty development, male breasts will change during puberty due to hormonal stimulation, which is a normal physiological phenomenon, and will return to normal after puberty. 2, endocrine disorders, if you take estrogen or do not inactivate estrogen because of liver problems, it will lead to endocrine disorders, and there will be feminization of the male breast, which will need to be discontinued and endocrine regulation. 3, breast enlargement or breast cancer, whether male or female will have breast diseases, need to go to the hospital for relevant examinations. Breast hyperplasia or breast cancer, no matter male or female will appear breast disease, need to go to the hospital for relevant examination, breast hyperplasia is a benign disease, if appeared need to take medication treatment, if necessary, surgery. If it is breast cancer, you need to carry out mastectomy, after surgery, regular chemotherapy, regular review, to prevent malignant changes.