The absence of bearded axillary and pubic hair is seen in Klinefelter syndrome. It is also known as congenital testicular hypoplasia or Klinefelter’s syndrome. The typical karyotype is 47, XXY, and the phenotype is characterized by testicular hypoplasia. The body is elongated, due to an increase in the distance between the heel and the toe bones. In men, the mammary glands are developed, pubic hair is distributed in a feminine pattern, and the penis and testes are small. Severe cases are associated with mental retardation, cryptorchidism and hypospadias. Sometimes it can occur due to some organic diseases, such as hypopituitarism, hypothyroidism, testicular feminization syndrome, etc. The genetic counseling is important for the prevention of beardless armpit hair and pubic hair because they are largely hereditary. (1) Subjects of genetic counseling: ①Patients with confirmed hereditary diseases and their relatives. (2) Families with continuous occurrence of diseases of unknown origin. (3) Those with congenital primary mental retardation, suspected to be genetically related. ④Carriers of balanced translocation chromosomes or pathogenic genes. ⑤Women with recurrent miscarriages of unknown cause. (6) Those with abnormal sexual development. (7) Those who have a family history of hereditary diseases and intend to marry or have children. (2) Main objectives of genetic counseling: ① For the patients themselves: A. Determine the diagnosis, cause, mode of inheritance, treatment and prognosis of the disease, and further analyze whether the patient’s disease-causing gene or chromosomal abnormality is caused by a new mutation or inherited from the previous generation. B.Reduce the physical and mental pain and anxiety of the patient. C. Give early attention to patients who have not developed the disease and give necessary treatment. ②For both parents and relatives: A.Detect carriers and recessive cases in the family. B. Determine the risk of disease in a member of the family. C. For couples at risk of having a child with a genetic disease, help them scientifically and consider birth plans according to the regulations of family planning. (3) Genetic estimation of pediatric diseases: ① To differentiate whether the disease suffered by the child is caused by intrauterine environmental factors, birth injury and hypoxia-ischemia or genetic factors. Therefore, we need to know the relevant medical history of both parents of the child (e.g., medication, nature of work, etc.), the mother’s pregnancy history, and the birth history of the child in order to exclude the damage to the embryo and fetus by various physical, chemical, and biological factors. ②Inquiry into family history and analysis of family tree is one of the basic methods of genetic counseling. ③According to the clinical manifestations, combined with relevant laboratory tests, a clear diagnosis is made. If it is a chromosomal abnormality disease must be combined with karyotype analysis to be determined. (4) To clarify the genetic characteristics of each genetic disease: It is of great significance for guiding fertility.