Turner syndrome is also known as congenital ovarian hypoplasia. There are 23 pairs of 46 human chromosomes, one of which is the sex chromosome, the X and Y chromosomes in boys and both sex chromosomes in girls. If a girl has only one X chromosome (i.e., X haplotype), or if part of the X chromosome is missing, she may develop Turner syndrome, which is congenital ovarian hypoplasia. Usually, about half of the patients with Turner syndrome have X monosomy and 20-30% have chimerism, which means that one part of the cell has only 45 chromosomes and one X chromosome is missing, while the other part of the cell may have 23 pairs of 46 chromosomes as normal, or one part of the cell may have Y chromosome or Y chromatin. The presence of Y chromosome or Y karyotype increases the risk of gonadal embryonal cell tumors and germ cell tumors with age, which may be associated with specific Y protein-encoding genes near the chromosomal attachment site. the presence of Y chromatin may also be associated with the production of non-tumorigenic abnormal androgens. Therefore, although the need for routine Y chromatin testing (in situ hybridization or PCR) in patients with Turner syndrome is controversial, it is advisable to test the Y chromatin of patients with Turner syndrome in hospitals or institutions that are able to do so. Patients with Turner syndrome who have a Y-chromatin karyotype should undergo laparoscopic gonadectomy even if the ultrasound image is unclear. However, in patients without evidence of gonadal dysgenesis and who have conceived spontaneously, the only thing that seems reasonable is close observation.