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 chromosomal abnormality of congenital testicular hypoplasia has more chances in pregnancy in women of advanced age, which can be referred to the relevant preventive measures for genetic diseases: 1. Prohibit marriage between close relatives and avoid pregnancy at advanced age. 2, premarital examination with a view to detecting genetic diseases or other diseases that should not be married. 3, carrier detection: through group census, family lineage survey and genealogical analysis, laboratory tests and other means to determine whether it is a genetic disease, and determine the mode of inheritance, etc. 4.Genetic counseling: (1) Genetic counseling target: ① Patients diagnosed with hereditary diseases and their relatives. (2) Families with continuous occurrence of diseases of unknown origin. (3) congenital primary mental retardation, suspected to be related to heredity. 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. To determine the diagnosis of the disease, the cause of the disease, the mode of inheritance, treatment and prognosis, and to 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. To alleviate 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 distinguish whether the disease is caused by intrauterine environmental factors, birth injury and hypoxia-ischemia or genetic factors, so we need to know the relevant medical history of both parents (such as medication, nature of work, etc.), the mother’s pregnancy history, the birth history of the child, etc. in order to exclude various physical, chemical and biological factors that damage the embryo and fetus. ②Inquiring the family history and analyzing the family tree is one of the basic methods of genetic counseling. (3) According to the clinical manifestations, combined with relevant laboratory tests, to make a clear diagnosis, such as chromosomal abnormalities in the disease must be combined with karyotype analysis to determine. (4) Clarify the genetic characteristics of each genetic disease: it is of great significance for guiding childbirth. 5, prenatal diagnosis prenatal diagnosis or intrauterine diagnosis, is an important measure of preventive eugenics, prenatal diagnostic techniques used are: ① amniotic fluid cell culture and related biochemical examination (amniocentesis time to 16-20 weeks of gestation is appropriate); ② maternal blood and amniotic fluid methemoglobin determination; ③ ultrasound imaging (about 4 months of pregnancy can be applied); ④ X-ray examination (after 5 months of pregnancy), for the diagnosis of fetal skeletal (5) sex chromatin determination of chromaffin cells (at 40-70 days of conception) to predict the sex of the fetus to help the diagnosis of X-linked genetic diseases; (6) application of gene chain analysis; (7) fetoscopy. The above techniques are applied to prevent the birth of fetuses with serious genetic disorders and congenital malformations.