(4) Gynecomastia is swelling ofthe breast tissue in boys ormen, caused by an imbalanceof the hormones estrogen andtestosterone.The developmentof gynecomastia is usually associatedwith benign pubertalchange. Disturbances in theendocrine system that lead toan increase in the ratio of estrogens/androgens arethought to be responsible forthe development of gynecomastia.