Someday, if the girl grows up to have a baby , her breasts can provide the milk the baby needs. Besides sports bras, there are a lot of other types of bras. Andria Castillo, now 17 and a junior at Mather High School in Chicago, says she remembers that when she was around that age, she was painfully self-conscious about her breast size; she thought she was developing more slowly than everyone else.
In general, it takes 4 to 5 years for a girl's breasts to reach their adult size. Sign up to get the latest news on parenting, child health and relationships with advice from our experts to help every family live well. Enter your email address below.