Pregnancy failure (spontaneous abortion and fetal abortion) is a common problem with various causes, mostly due to chromosomal abnormalities in the early stages (within 12 weeks) (more than 50%). The main male factors for pregnancy failure or recurrent pregnancy failure (3 or more consecutive pregnancies) are: 1. Chromosomal abnormalities (somatic or sperm. The former do lymphocyte karyotyping, which is commonly seen as a karyotype report. The latter do sperm polychromatic fluorescence in situ hybridization, which is rarely done), including numerical abnormalities (e.g., one extra or one less chromosome), structural abnormalities (e.g., chromosomal segments with deletions, duplications, reciprocal translocations, Robertsonian translocations, inter-arm inversions, etc.). The relationship between chromosomal polymorphisms (e.g., large or small Y, size and presence of follower, growth or shortening of secondary constrictions, etc.), which are often mentioned, and pregnancy failure is not clear. 2. Sperm DNA damage, i.e. single or double strand breaks in sperm DNA occur. Sperm with DNA damage can still be inseminated, and the oocyte has the function of repairing sperm DNA after the sperm-egg union, and if it is completely repaired, it will continue to develop and deliver a normal pregnancy. If the sperm DNA damage is severe (correlated with the age of the male partner, heavier than 35 years old) or the oocyte has weak repair ability (correlated with the age of the female partner), the result may be spontaneous abortion, fetal abortion or embryo malformation. Methods to detect sperm DNA damage include the Comet test (Comet) and the sperm chromatin diffusion test (SCD). 3. Abnormalities in routine semen parameters, such as sperm concentration (oligospermia), sperm motility (weak sperm) and sperm morphology (high sperm malformation rate,) are not clearly related to pregnancy failure. However, some malformed sperm, such as large-headed and multi-tailed sperm, may be sperm with abnormal chromosome number, which may cause pregnancy failure. 4, genitourinary tract infections, such as orchitis, epididymitis, prostatitis, vesiculitis and urethritis, etc. also have no clear relationship with pregnancy failure. 5, encounter the above problems countermeasures are as follows: (1) chromosomal abnormalities: genetic counseling, third generation IVF or artificial insemination by sperm donation; (2) heavy sperm DNA damage: investigate the cause, targeted adjustment or treatment (such as adjusting lifestyle, quit smoking, radiation protection, treatment of varicocele, etc.).