What if one of my breasts is bigger than the other? When breasts are growing, they change shape and size until they're fully developed. Along the way, one breast may be bigger than the other. Of course, a girl would rather them both be the same size. If this happens to you, stay calm: No. 1: You are probably the only one who has noticed. No. 2: Your breasts are likely to even out as you develop. And No. 3: If you still notice a difference after your breasts have fully developed, you can use a bit of padding in one bra cup to balance things out. See more Personal Questions Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.