Non-obstructive azoospermia is a condition in which the spermatogenic function of the testes is severely impaired or absent and no sperm is detected in the semen. The causes of azoospermia include congenital genetic factors such as Creutzfeldt-Jakob disease, which usually has an extra X chromosome compared to normal males, and the absence of a fertility-related gene fragment on the Y chromosome in some patients, which can be identified with current tests. There are also some acquired causes, such as a history of viral mumps with orchitis, chemoradiotherapy for tumors, and nuclear radiation. In most patients, there is no way to identify the specific cause of the disease. To make a definitive diagnosis, patients undergo a series of tests, including semen routine, seminal plasma biochemistry, sex hormone 5, ultrasound of the reproductive system, autosomes, and Y chromosome microdeletions, which can provide a general typing of azoospermia. A definitive diagnosis can be made by testicular puncture or biopsy, both of which are less invasive diagnostic operations, but testicular puncture only responds to the presence or absence of sperm, whereas testicular biopsy provides not only a diagnosis of the presence or absence of sperm, but also a pathological diagnosis.