Gynecomastia is a condition characterized by enlarged or swollen breast tissue in males. It can occur in one or both sides of the chest, and it can range in severity from being barely noticeable to being incredibly pronounced.  The condition can be found in males of all ages, but it is more common among newborns, boys going through puberty, and older men. Fortunately, gynecomastia is not a serious medical condition. That said, it can be physically uncomfortable and is often a source of embarrassment for men and boys.