The Doctors discuss the case of a teenage male who developed one A-cup breast and underwent a mastectomy for the unusual growth. His doctors are suggesting that hormones in fast food may be to blame.

Watch: Does Eating Chicken with Hormones Cause Men to Develop Breasts?

Breast specialist Dr. Kristi Funk says the hormone zearanol, a synthetic estrogen commonly used to make cows grow fatter faster, has been linked to breast growth in studies. Meat containing the hormone has been banned by the European Union, but zearanol is still used in some places in America.

The Doctors ask if the presence of the hormone in food matters and can it contribute to cancer?

Watch: Three Tips to Disguise "Man Boobs"  

Dr. Funk tells The Doctors that benign breast cells in a petri dish which have been exposed to zearanol can develop cancer in just 21 days. She also says that The Nurses Health Study (NHS), which tracked thousands of women for 7 years, reported a 34 percent bump in breast cancer among women who consumed red meat while in high school. The breast specialist feels so strongly about the health risk associated with meat and dairy, that she and her family are now vegan. 

The Doctors note that grass-fed beef does not contain the hormone in question. The Doctors say it is important to know how the animals you eat are raised and to always eat meat and dairy in moderation.