When are girls breast development normal?

Girls in about 10 years old, breast development is a normal phenomenon. But the specific time with the physical relationship, there are some girls may develop early, in the performance of breast development phenomenon, to timely go to the hospital pediatrics for examination. If premature development, need to timely take drugs to reduce body sex hormones to control. Girls in 10 years old, showing breast development phenomenon, be sure to choose the right underwear, do not wear tight underwear, too tight underwear will affect the normal development of the breast.