Many young women will develop breasts and hips during puberty—the hormone estrogen (E) helps to jump-start it.
Breasts come in many shapes and sizes—some larger, some smaller, and some inbetween. Often, the two breasts are not exactly the same size. Breasts also change with your age and body weight. If you get periods they will sometimes also change slightly at different points in your menstrual cycle.
There is no standard breast size; there is only you and your body.
For some young women who aren’t developing breasts or who don’t produce the hormone E, doctors may discuss taking estrogen medication, to start breast and hip development—this is called hormone therapy. If you are interested or want to learn more about hormone therapy, talk to your doctor at your next visit.