Gynecomastia or
Gynaecomastia,
/ˌɡaɪnɨkɵˈmæstiə/, is the abnormal development of large
mammary glands in
males resulting in breast enlargement. The term comes from the
Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast." The condition can occur physiologically in
neonates, in
adolescence, and in the elderly. In adolescent boys the condition is often a source of distress, but for the large majority of boys whose pubescent gynecomastia is not due to
obesity, the breast development shrinks or disappears within a couple of years.