The causes of gynecomastia are yet to detected as these are shrouded in mystery. However, the hormonal imbalance due to malnutrition or otherwise causes gynecomastia. The increase in estrogens and decrease in andgrogens enlarges the breast tissue. The causes are physiologic, non-physiologic and chronic disease.
The diseases which can lead to the growth of male breast are kidney failure, liver disease, hyperthyroidism, underproduction of testosterone, obesity, etc.
Also, it can be a result of various drugs and medications like antibiotics, steroids, narcotic drugs, chemotherapy, heartburn medications, HIV medication, herbals like tea tree oil and lavender, etc.
In some cases, the cause remain unknown till date.
It goes on its own at the puberty stage but needs treatment if it persists.