1. duration of infertility: when the inability to have children without contraception lasts more than 4 years, the chances of a natural monthly pregnancy are low. 2, is the primary or secondary infertility: in the case of normal fertility of one party, the chances of both couples to obtain fertility depends mainly on having absolute or relative infertility of one party cured. 3, semen analysis results: semen analysis is an important basis for assessing male fertility, abnormal results suggest the presence of reduced fertility, the semen parameters most closely related to fertility is the number and viability of sperm. The majority of those with a total number of active sperm greater than or equal to 40 million can get pregnant through sexual intercourse between the two partners; 5 million to 40 million can be considered for IUI pregnancy; those greater than zero and less than 5 million should strive for in vitro pregnancy. 4, the age of the woman and fertility: women’s fertility at age 35 is only 50% of that at age 25, drops to 25% at age 38, and further drops 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.