Moobs is what the term on the street is for man boobs, and it refers to enlarged breasts in boys and men. This condition is called gynecomastia. It’s fairly common for boys and men to have their breasts swell, and before this, it was thought to be a cause of obesity. Usually, obese or overweight men and boys are more likely to have this condition, but slender, thin men also have the tendency to have them, especially boys in their teenage years and men who are older.