Man boobs, or its medical term, gynecomastia is a relatively common condition in men which describes the formation of enlarged breast tissue. It is very common in young babies, including neonates and young boys around the age of puberty. This is due to the fluctuating hormone levels in these age groups and will normally correct itself over time.
In the post pubescent age group, such as young men and older, the problem may be due to other causes and be more difficult to get rid of. The most common cause, however, is being overweight. It does not necessarily have to be overweight to the point of being obese because it can occur even if you are slightly overweight. The most common reason for this is that some men have more fat cells deposited in the breast area and so it is a common place for any fat to collect.
If you are overweight then, even if you do not have more fat cells deposited here, the fat tissue is actually going to get bigger as it is every where else in the body. If you are overweight, you generally have more fat in the body. This fat tissue makes the female hormone estrogen which, as in women, causes breast development. Therefore, if you have more fat tissue and, therefore, more estrogen in the body this is further going to increase your risk of developing man boobs.
Medication is another common cause of man boobs. It is not just taking estrogen that is going to increase breast development. Many body builders often find, when taking testosterone, they develop man boobs. The reason for this is that some of the testosterone is actually converted to estrogen in the body.
For this reason, many body builders whom are taking testosterone often take additional drugs to counteract this, like the breast cancer drug tamoxifen. There are other non-hormone medications that can cause man boobs such as cimetidine, spironolactone, finasteride and omeprazole
Man boobs can sometimes be as a result of an underlying medical problem such as kidney disease, some tumors like testicular tumors and liver disease. These illnesses often cause gynecomastia by, again, increasing the body's levels of estrogen by either producing more of it or by reducing its breakdown and metabolism. Therefore in adult men who develop excess breast tissue it is often advisable to consult your physician to exclude any underlying diseases.
If there is an underlying cause for the gynecomastia then it may go some way into determining the treatment. For many men, however, the cause is unknown or is is due to excess fat from being overweight.