Is it normal for breasts to be large and small on one side?

Breast size is a normal phenomenon, the patient shows this situation has the following reasons: 1. Embryonic development process, one side of the breast development is larger;2. Adolescent girl breast development, one side of the breast is more sensitive to hormone levels, resulting in different breast development speed on both sides, such as mature development, the gap is not big;3. Women in lactation breast milk content is different, if the patient congenital or adolescent development after the two sides of the breast difference is particularly large, should go to the hospital for treatment.