On Monday morning, a tall, sunny and handsome young man, Xiao Zhang, entered the male outpatient clinic of the Reproductive Center of Shanghai Sixth People’s Hospital. Xiao Zhang told Dr. Liu, who was attending to him, his frustration: He had been married for almost 2 years, and his married life had been normal, but he could not conceive. The wife went to the hospital to check everything is normal, and his own health has always been great, there should not be a problem. Dr. Liu gave Zhang a careful physical examination, and then sent Zhang to do a routine semen examination. The results came out an hour later and there was no sperm in the semen. Xiao Zhang could not believe it, Dr. Liu explained to him that normal couples are not pregnant after 1 year of marriage without contraception is called infertility, and now the incidence of infertility is increasing, about 1 in 7 couples, 50% of which are related to men, should be checked in the hospital. The common causes of male infertility are oligospermia, azoospermia, and semen non-liquidity. If there is no sperm in 2 or more semen tests, it is clinically called azoospermia. Azoospermia is an important factor in male infertility. Under the action of gonadotropins produced by the hypothalamus and pituitary gland, spermatozoa are mainly produced by spermatogenic cells of the testes and discharged through the epididymis, vas deferens, seminal vesicles and ejaculatory ducts. Therefore, the common causes of azoospermia can be divided into pre-testicular, testicular and post-testicular factors. Pre-testicular causes are mainly hormonal abnormalities caused by pituitary lesions in the hypothalamus, resulting in the spermatogenic function of the testes being affected, such as patients with Kallmann syndrome, who have congenital gonadotropin-releasing hormone synthesis disorder, resulting in testicular hypoplasia, accompanied by olfactory impairment, and patients with pituitary tumors, who will have decreased gonadotropin or increased prolactin, thus causing azoospermia. Testicular sexual factors commonly include cryptorchidism, mumps orchitis, Crohn’s syndrome, varicocele, impaired testicular spermatogenesis caused by environment, radiation, etc. Post-testicular factors are mainly caused by obstruction of the sperm output tract, such as damage to the vas deferens from hernia surgery as a child, obstruction after epididymal inflammation, obstruction of the ejaculatory duct opening, and congenital absence of the vas deferens. Dr. Liu suggested that Zhang review his semen examination 1-2 times, and at the same time draw blood for sex hormones, chromosomes, urogenital tract ultrasound and other examinations, and perform testicular aspiration biopsy if necessary. After the cause is clearly identified, symptomatic treatment can be given. For pre-testicular low gonadotropin infertility, gonadotropin treatment can be used, and pituitary tumors can be treated with surgery or medication, and the efficacy of most of these patients is relatively certain. For azoospermia caused by testicular factors, treatment can first be done by removing the cause, if still azoospermic, testicular puncture biopsy or excisional biopsy can be used, if sperm is found, IVF technique can be used, where sperm is injected into egg cells in vitro, and embryos are formed by laboratory culture and finally placed in the mother’s uterus. If the azoospermia is caused by post-testicular obstruction, surgery can be used to release the obstruction to obtain fertility, or epididymal or testicular puncture can be used to obtain sperm and then perform assisted reproductive technology treatment, most people can still have offspring. After listening to Dr. Liu’s explanation, Zhang had a preliminary understanding of azoospermia. It seems that having children is not only a woman’s business, but also a man’s responsibility!