What are the causes of azoospermia? The causes of azoospermia can be categorized into pre-testicular factors, testicular factors and post-testicular factors depending on the location. Pre-testicular factors include chromosomal abnormalities, hypothalamic and pituitary disorders causing testicular dysplasia. Testicular factors mainly include cryptorchidism, testicular tumor, trauma, orchitis and testicular lesions caused by systemic diseases or tumors after chemotherapy and radiotherapy. Post-testicular factors are mainly obstruction or dysplasia of the epididymis and vas deferens, or medical injury (e.g., vasectomy or surgical malpractice). How is the cause of azoospermia determined in patients with azoospermia? First of all, we should know in detail about the patient’s growth and development history, past medical history, marital history, etc.; secondly, we should carry out a detailed physical examination, including secondary sexual characteristics such as beard, laryngeal knots, body hair and the development of external genital organs, especially the size and texture of testes and whether there are hard nodules of dysplasia in the epididymis and vas deferens, etc.; thirdly, we should carry out semen laboratory tests, at least two times and centrifuge semen to look for sperms; fourthly, we should carry out the measurement of reproductive hormones. According to the hormone levels, the spermatogenic function of the testes can be generally determined; Fifth, chromosome and Y chromosome examination, to determine whether there are chromosomal abnormalities caused by azoospermia; Sixth, some patients can undergo ultrasound and other imaging tests, to understand whether there are prostate, seminal vesicles and vas deferens pathology or dysplasia How to treat patients with azoospermia? The first step is to try to find the cause of the disease and treat the cause. For patients with hypothalamic pituitary lesions, some of them can produce sperms and even give birth through medication before the age of 20; for drug-induced azoospermia, the drug should be discontinued, and some of the patients are expected to regain spermatogenic function; however, for most of the patients who have undergone chemotherapy or radiotherapy for tumors, it often leads to irreversible lesions in the testes; for vas deferens blockage caused by surgery or trauma, anastomosis of the vas deferens can be carried out; for patients with vasovaginal disease caused by surgery, anastomosis can be carried out. For patients with ejaculatory duct cysts or occlusion, the ejaculatory duct can be incised or the cyst can be removed transurethrally. However, for most azoospermia patients, the goal of having children on their own cannot be achieved through general treatment. For patients with well-developed testes and normal spermatogenesis, they can puncture the testes or epididymis to obtain sperm, and then undergo IVF treatment; for patients with underdeveloped testes and poor spermatogenesis, artificial insemination with sperm from a sperm bank is the best choice.