This is a great question. In general, breast growth and development is complete between ages 17-21 years. By the age of 18, the vast majority of female patients will have completed their breast development. A woman's age and breast growth is taken into consideration by plastic surgeons when discussing certain breast procedures with patients, especially younger patients. That is one important reason why the consensus among most of US board-certified plastic surgeons and the American Society of Plastic Surgery is to wait until the age of 18 before considering breast augmentation or enhancement. That being said, the breast size and shape continues to evolve through out a woman's life and are affected by such things as pregnancy, breast feeding, weight fluctuation, and menopause. These factors are taken into consideration for all cosmetic breast surgeries, such as breast augmentation, breast lift, and breast reduction. When considering cosmetic breast surgery, I strongly recommend consulting with a Board-Certified Plastic Surgeon to discuss your option. Best wishes, Andrew Lyos MD, FACS