Male infertility accounts for the highest proportion of male outpatients, and there are many causes of male infertility, roughly divided into: absolute infertility and relative infertility; primary or secondary infertility? Subdivision: pre-testicular, testicular, and post-testicular. Pre-testicular – mainly endocrine factors, such as hypothalamic lesions, pituitary lesions and fertility-related hormone abnormalities. Testicular sexual – mainly there are chromosomal abnormalities and other factors that cause testicular damage; chromosomal abnormalities such as klinefelter syndrome, XXY syndrome, XX male syndrome, Noonan syndrome (male Turner syndrome), Y chromosome microdeletions and other chromosomal abnormalities; testicular Injuries, mainly varicocele, orchitis, radiotherapy, chemotherapy, environmental toxins, malnutrition cryptorchidism, etc. Post testicular sex – mainly sperm dysfunction or motility disorders caused by obstruction of the vas deferens, immune infertility, sexual intercourse or ejaculation disorders, etc. Male physicians, often based on the medical and family history of the friend attending the clinic, combined with physical examination and laboratory tests, initially determine whether it is testicular? The next step in the process is to determine whether it is pre-testicular or post-testicular. The next step is to conduct a targeted test! One of the very targeted tests is chromosomal examination. According to my clinical experience, I believe that chromosomal examination is necessary in the following cases: 1, some severe oligospermia, weak sperm or azoospermia, high blood FSH index, physical examination found that the secondary sexual characteristics are not obvious, or the testicles are soft and small; 2, severe hypospadias, that is, the urethra and spongy body dysplasia resulting in abnormal urethral opening position congenital anomalies; 3, hermaphroditism malformations (also known as abnormal sexual differentiation), attributed chromosomal genetic disorders; 4, some congenital seminal vesicle defects or congenital vas deferens, etc.; 5, those who are highly suspected of having chromosomal disorders.