Gynecomastia can be defined as the presence of any excess tissue on a male chest and it is often breast tissue mixed with fatty tissue. It frequently occurs in three phases of life. It can occur in a newborn, but frequently disappears. It often occurs during puberty and disappears in many young men, although it may persist forever in some of them. It can also occur later in life due to a variety of factors, which include various diseases (including some cancers), hormonal irregularities, use of bodybuilding (anabolic) steroids, various supplements, marijuana, side effects of various medications, etc.
Oftentimes, there are strong hereditary factors as well. Gynecomastia is not related to obesity but may coincide with it. It may be as small as a firm area of tissue just under the nipple or as large as a DD cup pendulous breast.
