As summer arrives, the growth and development clinic is seeing more girls, as in previous years, most of whom are brought in by their parents to see their breast development. It is normal for girls to develop breasts when they reach the age of 8 years or older. However, the earlier the development, the greater the impact on the eventual adult height. It is well known that early maturity can lead to short stature. The time between breast development and the first menstruation varies from person to person, usually 1 to 3 years. This is based on the level of sex hormones in each child’s body, with some developing slowly and others progressing rapidly. The increase in the level of sex hormones in the body will accelerate the progression of bone age, and once the bone age closes the growth of height will stop. In general, the height potential after the first menstruation is around 5 cm (2 cm to 8 cm). Some parents also know that their child has already developed and that their height is not ideal. However, considering various factors, they are indecisive and delay in deciding whether to intervene for treatment. It is not until the child’s menarche that the child is determined to be treated, not knowing that the effect of intervention at this time is far less than early intervention, because the girl’s menarche indicates that her growth has entered the middle and late stages, and her epiphysis is about to close, which means that there is not much room for growth. Not long ago, a girl came to the clinic and was seen at the specialist clinic 2 years ago when she had her first menstruation. Two years later, she came back to the clinic today and her height was only 149 cm. Unfortunately, the bone age was completely closed. Here is a reminder to parents: if a girl above 8 years old has breast development and her basic height is good, i.e., she is above average height in her class, she can be observed at home and does not need to go to the hospital urgently. However, for those who are not tall, or whose parents are not tall enough, it is best to go to a specialist clinic as soon as possible. For girls who are menstruating for the first time, if their height is less than 150 cm, they should also come to the hospital for examination as soon as possible.