Most children with Turner syndrome have hypogonadism. About one-third of girls with Turner syndrome may have spontaneous puberty, but only half of them have their first menstrual period. Pregnancy is an exceptional event, but it can occur in 2% of Turner syndrome patients. Why do children with Turner syndrome have hypogonadism? Humans have 23 pairs of 46 chromosomes, one of which is a sex chromosome. Boys have one X chromosome and one Y chromosome each, and girls have both sex chromosomes as X chromosomes. If a girl has only one X chromosome, or if part of the X chromosome is missing, she may develop Turner syndrome, which is congenital ovarian hypoplasia. Because the X chromosome contains many genes (1000), the loss can cause many problems or even serious problems, with gonadal insufficiency being one of the main problems. In fact, a Turner syndrome fetus can have millions of germ cells in the middle of the mother’s gestation, but then they rapidly decrease, leaving only a few follicles in the fibrous cords at birth, resulting in gonadal insufficiency. Are the vast majority of children with Turner syndrome infertile? There are two reasons for this: one is chimeric Turner syndrome, in which some cells have a normal 23 pairs of 46 chromosomes and some cells have only 45 chromosomes, with one X chromosome missing, and the higher the percentage of normal cells, the less severe the gonadal insufficiency. In the other case, although the number of chromosomes is normal, the chromosome structure is abnormal, but it happens that the gene controlling ovarian function (in the Xq13-q26 region) is still normal and therefore ovarian function is preserved. Adult women with Turner syndrome who are unable to conceive naturally may now have the opportunity to become mothers through assisted reproductive technology.