1.Etiology of azoospermia About half of the azoospermia cases are caused by blockage of the vas deferens. Common factors that cause blockage include: inflammation of the genitourinary system (e.g. epididymitis, reproductive tract tuberculosis), developmental abnormalities (e.g. vas deferens, seminal vesicle defects), medical injuries (e.g. vasectomy, inguinal hernia device surgery), etc. The non-obstructive causes of azoospermia are more complex, with common etiologies: genetic abnormalities (e.g., Crohn’s syndrome, Y chromosome microdeletion, certain chromosomal translocations), cryptorchidism, mumps combined with orchitis, endocrine abnormalities (e.g., congenital Kaman syndrome, or acquired pituitary surgery), various radiotherapy injuries, and unexplained testicular dysplasia. The main concerns of patients who visit the clinic are: whether I will be able to find sperm and have my own offspring; and whether there will be serious offspring abnormalities due to the male partner’s etiology. To answer these questions, it is necessary to improve the relevant tests and first look for answers to the causes of azoospermia. For azoospermia, we routinely perform the following tests: (2) Routine semen analysis and post-centrifugal examination (at least three times) Meaning: To confirm the absence of sperm in semen; because the semen test results themselves fluctuate greatly, in the case of very low sperm count, there is a possibility of missing a single test, and rechecking, together with post-centrifugal observation, will increase the probability of finding sperm. (2) Biochemical examination of seminal plasma Meaning: To find out whether azoospermia is caused by obstruction of the vas deferens, and to evaluate the site of obstruction and the possibility of surgical correction of azoospermia. (3) Sex hormone examination Meaning: To evaluate the spermatogenic function of the testes and to understand whether there are endocrine causes that can be corrected; for some patients with significantly lower FSH and LH, it is very likely that sperm can be produced gradually through hormone treatment. (4) Genetic examination (karyotype, Y chromosome microdeletion) Meaning: To understand whether azoospermia may be caused by genetic abnormalities and to assess the success rate of testicular biopsy for sperm retrieval and the safety of having offspring. (5) Depending on the condition, scrotal ultrasound and urine examination to find sperm may also be required. 2. How to find sperm and conceive in azoospermia For patients with azoospermia caused by obstruction of the vas deferens, we can help them conceive by aspirating sperm from the testicles or epididymis and then performing intracytoplasmic single sperm injection (i.e. “second-generation IVF”) with the female partner; the aspiration procedure takes less time, causes less damage, does not require hospitalization, and can be done after resting for half an hour. The sperm aspiration procedure is shorter, less invasive and requires no hospitalization, and the patient can leave after half an hour of rest. In the case of azoospermia due to testicular spermatogenic dysfunction, testicular sperm aspiration can also be attempted to obtain sperm. Since 2013, our center has introduced microscopic testicular sperm retrieval technique and has accumulated some experience in the related field, successfully obtaining sperm by surgery for patients with various etiologies such as severe testicular dysplasia (2 ml, about the size of peanut rice), greatly elevated blood FSH (>70 IU/L), advanced age (60 years), testicular spermatogenesis failure after chemotherapy, etc. 3.Repair of vas deferens obstruction In order to meet the patient’s desire for natural fertility, in addition to in vitro fertilization (i.e. “IVF”) technology, we can also arrange for epididymal-vas deferens anastomosis recanalization surgery for patients with azoospermia caused by epididymal and vas deferens obstruction. This surgery is mainly for patients with azoospermia caused by inflammation of the epididymis or vasectomy, and even for couples who choose IVF in the future, the successful repair of the vas deferens can reduce the pain of repeated puncture for sperm retrieval by the male partner. For patients with severe sperm production disorders, finding sperm is as difficult as finding a needle in a haystack, and in many cases, there may only be one or two chances to find sperm. In order to reduce the risk of the male partner having no sperm available on the day of egg retrieval, we provide sperm cryopreservation service for patients undergoing outpatient testicular puncture, in addition to routine testing for the presence of sperm, as a backup to the sperm used by the female partner on the day of egg retrieval, so as to minimize the occurrence of accidents. For some cases where the female partner has reduced ovarian function and fewer eggs are retrieved each time of IVF, frozen sperm reserve can also reduce the pain and psychological pressure caused by the male partner’s need for repeated punctures to retrieve sperm. In cases where all kinds of treatments fail to obtain sperm or the male partner is diagnosed with serious genetic abnormalities, couples can choose to receive sperm donation to help them conceive; our center can perform “in vitro fertilization” for couples with female infertility factors or those who have repeatedly failed in sperm donation at outside hospitals. If you need it, please bring all your previous test results and medical records to our hospital for registration.