Do men have mammary glands or not? Many men with gynecomastia have the concern, “Why do I have a woman’s mammary gland?” during their consultation. Some doctors also base their decision to operate on the presence or absence of glands. Today, we are going to educate ourselves about this issue. Let’s be clear: we are all born with mammary glands, male or female. In general, the male mammary gland gradually regresses around one and a half years of age, and the gland contains only ducts, no alveoli and is not lobulated (the gland degenerates to a very small size but still exists). During adolescence, some male mammary glands develop abnormal neurological and hormonal growth, resulting in a feminine breast appearance. Clinically, gynecomastia (male breast enlargement) is diagnosed when the male breast gland develops abnormally to a size greater than five millimeters. Gynecomastia is a benign disease that does not affect the normal work and study life and is not a cause for concern. The development of the mammary glands is not a major factor in determining whether to operate or not.