(a) Definition of male infertility World Health Organization (WHO) stipulates: ① Couples who have lived together for more than 1 year without using any contraception ② Female infertility due to male factors. Note: Male infertility is not an independent disease, but the result of one or many diseases and/or factors [1]. (ii) Epidemiology of male infertility ① According to WHO survey, 15% of couples of childbearing age have infertility problems, while in some areas of developing countries it can be as high as 30%, with 50% of causes for both men and women. ②Reports show that the overall semen quality of men in China is decreasing at a rate of 1% per year. (③But the claim that the quality of male semen is declining year by year is controversial. Some studies have shown a downward trend in sperm concentration, but little change in sperm vitality. (C) male infertility factors 1, the duration of infertility under normal circumstances, the fertility of normal couples with a single month pregnancy rate of 20% to 25%, six months pregnancy rate of 75%, 1 year pregnancy rate of 90%. Infertility for more than 4 years, the monthly pregnancy rate is only about 1, 5%; 2, primary or secondary infertility: primary male infertility is mostly due to hypospermia or disorders, can also be due to congenital developmental abnormalities. Secondary male infertility is mostly caused by acquired factors, including medical injury, reproductive system infection, etc. Usually, fertility can be restored through treatment or through assisted reproductive techniques to obtain their own offspring; 3. Semen analysis is an important basis for assessing male fertility, and abnormal results indicate reduced fertility. Among semen parameters most closely related to fertility are total sperm count and viability, while sperm morphological testing is an important reference for predicting the success rate of in vitro fertilization-embryo transfer (IVF-ET); 4. Female partner’s age and fertility Female partner’s fertility at age 35 is 50% of that at age 25, decreasing to 25% by age 38. It decreases to 25% by age 38 and can further decrease to less than 5% beyond age 40. Despite the advances in assisted reproductive technologies and their optimization, the age of the woman is still one of the most important factors affecting the success rate of pregnancy.