Congenital ovarian hypoplasia is one of the common causes of short stature and abnormal pubertal development in girls. It is caused by sex chromosomal abnormalities and occurs only in girls, with an incidence of 1/2000 to 1/5000 of live births. Most of the children are clinically short in stature. Their length and weight at birth may be lower than the normal average, and some of them are younger than gestational age. Their height is normal until 2-3 years of age, and after 3-4 years of age, their height increases slowly and they are often shorter than girls of the same age. Due to the X chromosome abnormality, most of the affected children have underdeveloped gonads and ovaries, and even have fibrous bundle atrophy, so that by the age of puberty, there is no acceleration of height growth during puberty, and the height lag is most obvious when compared with normal girls of the same age at around 14 years old. The normal female karyotype is 46,XX, which means that there are two X chromosomes. The typical karyotype of a child with Turner syndrome is 45, XO, which is one X chromosome less than a normal girl, and there are many other abnormal karyotypes (see Table 1). The cause is the complete or partial loss of an X chromosome before or during cell division. In Turner syndrome, approximately 95% of fetuses with karyotype 45, XO are spontaneously aborted before 28 weeks of gestation, whereas fetuses with XO/XX chimeric karyotypes are more likely to be viable and less severe. In the XO/XX chimeric karyotype, the higher the percentage of XO cells, the more malformations there are; conversely, and the lower the percentage of XO cells, the less malformations there are.