A: Each of the three methods has its own indications, advantages and disadvantages, and it cannot be considered that one is better than the other. Intravaginal artificial insemination is closer to physiology, and the sperm is screened layer by layer, which achieves the effect of survival of the fittest and avoids the potential dangers such as bleeding and infection caused by the latter two. Once pregnant, the abortion rate and deformity rate are also lower than the latter two in theory. Intrauterine artificial insemination makes some sperm directly enter the cervical canal, which increases the chances of sperm entering the uterine cavity, thus increasing the chances of pregnancy. In practical application, the first two are often combined. That is, a part of sperm is injected into the cervical canal (because the capacity of the cervical canal is limited, generally around 0.3 ml). While the rest is placed on the cervix. Intrauterine artificial insemination is more suitable for severe oligozoospermia, cervical abnormality, abnormal interaction between sperm and cervical mucus, unexplained infertility, etc., but it is limited in practical application because of its potential risks such as bleeding, infection, abortion rate and deformity rate. In short, we must strictly control all indications.