Azoospermia is one of the common causes of male infertility and is categorized into obstructive azoospermia and non-obstructive azoospermia. The latter is often caused by spermatogenic dysfunction, while the former, as the name suggests, is a condition in which the path of sperm is blocked, unable to swim into the seminal fluid, and naturally unable to combine with the female partner’s egg, making it impossible to conceive a baby naturally; this kind of azoospermia cannot be solved by medication, and has to be treated by surgery. Common obstruction sites are as follows: testicular outlet obstruction (i.e. obstruction of the output tubules), epididymal obstruction, and also vas deferens obstruction (e.g. vasectomy), ejaculatory duct obstruction, of which epididymal obstruction is the most common. Epididymal obstruction can be achieved through microsurgery by connecting the vas deferens to the epididymis to allow semen to pass through and achieve a natural pregnancy; however, in the case of testicular outlet obstruction or vas deferens high level obstruction, which cannot be solved by surgery, the only solution is to retrieve the sperm by puncture and achieve a pregnancy through second-generation IVF. Schematic diagram of testis, epididymis and vas deferens During the consultation process, apart from palpation examination, the doctor will also ask the patient whether he/she has undergone hernia surgery when he/she was a child. For a variety of reasons, a child’s vas deferens is damaged during the surgery but will not show any symptoms until they become infertile as an adult and the problem is not detected until sperm cannot be found. This type of patient can also have surgical rejuvenation at North University Men’s Center. If the vas deferens is of the right length, rejuvenation can be achieved through laparoscopic surgery, but it is more difficult to perform. Lastly, we would like to add that varicocele is also one of the common causes of male infertility, which may lead to severe oligozoospermia or even azoospermia, but does not cause obstructive azoospermia; prostatitis is one of the common diseases in male medicine, but this disease is not related to obstructive azoospermia.