Gynecomastia is a condition that is seen in boys or men in which the breast gland tissue becomes enlarged, and this happens mainly due to a hormonal imbalance. The hormones involved in the process are testosterone and estrogen. It is not mandatory for gynecomastia to affect both breasts equally. It can happen unevenly and sometimes; it might affect only one breast. Oftentimes, the symptoms do not require any form of treatment and go away on their own, but in some cases, surgery might be needed.

Tenderness or pain in the breast glands is usually noticed, along with a discharge from the one or both of the nipples. Gynecomastia takes place when the amount of testosterone in the body becomes less as compared to that of estrogen.