It is not a must to treat gynecomastia. It should be corrected only for cosmetic purpose or appearance purpose. Otherwise you feel shy to remove baniyan in the sports ground or in the swimming pool.
Whereas if gynecomastia is proved to be a pathological one after the examination and investigation, it must be removed.
In 95% of gynecomastia it is normal physiological. In 5% of the case only it is pathological and disease.