Yes, some people have one breast that is bigger or a different shape than the other. During puberty, when breasts are growing, they change shape and size until they are fully developed. During this time, you may notice that one breast is bigger. Breasts usually even out as they develop, but if they end up being slightly different sizes that’s normal too. If you notice that one breast is all of a sudden larger than the other or you’re worried about your breasts, talk to a health care provider.