Definition of male infertility:According to the World Health Organization (WHO), a couple who has lived without any contraception for more than one year and whose female partner is infertile due to male factors is called male infertility. Male infertility is not an independent disease, but the result of one or many diseases and factors. According to the WHO survey, 15% of couples of childbearing age have infertility problems, and in some areas of developing countries it can be as high as 30%, with both men and women accounting for 50% of the causes. Over the past 20 years, the sperm density of Western men has declined at an average rate of 2.6% per year, and the proportion of normal sperm and motility have declined by an average of 0.7% and 0.3% per year, respectively. The Institute of Science and Technology of the Population and Family Planning Commission of China studied the sperm analysis data of 11,726 people from 39 cities and counties, including Beijing, Shanghai and Tianjin, published between 1981 and 1996, and found that the semen quality of Chinese men was declining at a rate of 1% per year, and the number of sperm decreased by more than 40%. The main prognostic factors affecting infertility are: 1. duration of infertility: when no contraception is used and the inability to have children exceeds 4 years, the monthly pregnancy rate is only about 1.5%. 2, whether the infertility is primary or secondary: in the case of normal fertility of one partner, the chances of the couple to obtain a child depend mainly on curing the one with absolute or relative infertility. 3. Results of semen analysis: Semen analysis is an important basis for assessing male fertility, and abnormal results suggest the presence of diminished fertility. The semen parameters most closely related to fertility are sperm count and viability, while morphological examination of sperm has an important reference value for predicting the success rate of in vitro fertilization-embryo transfer (IVF-ET). Most of the total number of active sperm greater than or equal to 40 million can be conceived through mutual intercourse; 5 million to 40 million can be considered to take IUI pregnancy; those greater than zero and less than 5 million should strive to use IVF-ET and intracytoplasmic single sperm microinjection (ICSI) to conceive. 4, the age of the female partner and fertility: female fertility at age 35 is only about 50% of that at age 25, drops to 25% at age 38, and may further drop to less than 5% at age over 40. In assisted reproduction, the age of the woman is the most important factor affecting the success rate.