Infertility is categorized into infertility and sterility. Infertility occurs when an adult man and woman cohabit and have normal sexual intercourse for more than one year without using any contraception. Infertility is caused by the woman, and infertility is caused by the woman who is able to conceive but is unable to have a viable baby due to miscarriage for various reasons. Infertility in a male partner is called male infertility. 5 factors that can easily lead to infertility】 1, sexual dysfunction, including impotence, premature ejaculation, spermatorrhea, ejaculation, etc.. Abnormal semen quality, including oligospermia, azoospermia, necrospermia, hypospermia, polyspermia, hypospermia and semen non-liquefaction. 2, immunological factors, refers to the presence of anti-sperm antibodies in the man’s serum or seminal plasma, producing its own anti-sperm immune response, leading to immune infertility. 3, varicocele reproductive tract infections, congenital abnormalities, systemic diseases and infertility caused by unknown reasons. 4, environmental factors, air pollution, automobile exhaust, paint, radioactive radiation, high temperature working environment, etc. will cause semen quality decline. 5, bad lifestyle factors, smoking, drinking, staying up late, irregular life. Male infertility need to do these tests (1) semen analysis, sperm deformity rate, seminal plasma biochemistry: is the infertility of the mandatory items, the examination includes color, volume, liquefaction time, pH, sperm count, activity, survival rate and morphology, semen can respond to the function of accessory glands of the trace elements and so on. (2) In vitro heterologous fertilization test: routine semen analysis is completely normal, sometimes it can not fully represent the fertilization ability of sperm, in vitro heterologous fertilization test can make up for its shortcomings, and it is very valuable for determining the fertility of a man, and commonly used is the heterologous fertilization test in which the sperm of a man penetrates the egg of a hamster. The sperm fertilization rate of fertile men is reported to be 14%-100%, and less than 10% can be regarded as infertility. (3) Sperm penetration test: including post-coital test, sperm capillary penetration test, sperm cervical mucus slide penetration test. (4) Prostate Fluid Examination: Prostate fluid is usually collected by massage. Normal is milky white, alkaline, high power microscope can see a full field of lecithin particles, a few epithelial cells, amyloid and sperm, white blood cell count <10. When there is inflammation, the number of white blood cells increases, or even see heaps of pus cells, lecithin particles are significantly reduced. (5) Endocrine examination: plasma testosterone level, human chorionic gonadotropin stimulation test, gonadotropin-releasing hormone stimulation test, clomiphene citrate stimulation test and so on, to understand the function of hypothalamus-pituitary-testis axis. If necessary, adenocorticotropic hormone, thyroid hormone or prolactin can be measured. The first thing you need to do is to get a good understanding of the reasons for female infertility, even if your own physical signs seem to be healthy, you need to check with your wife, especially for a semen test, because infertility is likely to be insidious. 2, such as semen routine examination is normal, can rule out male infertility semen routine examination results are normal, does not mean that men have good fertility. Because the routine semen examination is only the number of semen, smell, color, liquefaction time, as well as the number of spermatozoa in the semen, motility, activity rate, morphology and other aspects of the preliminary understanding, but not be able to accurately determine the internal structure of the spermatozoa is normal, as well as the ability to fertilization and the integrity of the genetic material in line with the requirements of the fertility of the further examination can only be a definitive diagnosis. 3, semen examination can only be done once The results of a semen examination will be disturbed by many factors, such as the interval between the semen collection and the last ejaculation, whether the man has had a sauna in the 2 weeks before the semen collection, and whether the man has recently taken medicines to change the vitality of sperms, etc. Therefore, the results of a semen examination can not accurately illustrate the real condition of semen, and the results of more than 2 consecutive semen examinations within 2 weeks are needed to draw conclusions. It is necessary to conduct 2 or more semen tests within 2 weeks before a conclusion can be drawn.