The sperm and egg unite to form a fertilized egg, which is then planted (also called implanted) on the endometrium to grow and develop, called conception. Conception is a relatively complex process, to complete the process, the couple must have certain fertility conditions, these fertility conditions can be broadly divided into the following aspects. 1, the man’s testicles can produce normal sperm Normal adult men ejaculate a volume of 2-6 ml, the number of sperm per ml of semen should be more than 60 million, sperm with the ability to move more than 60%, abnormal sperm in the 15-20% or less. If the sperm does not reach the above standards, it will not be easy for the woman to conceive. 2. A woman with normal menstruation has a healthy and mature egg in each menstrual cycle so that she can have a chance to conceive. For women with incomplete ovaries or abnormal menstruation, it is not easy to conceive. 3, before and after the female ovulation period should have a normal sex life, so that sperm and eggs have the opportunity to meet and fertilize sperm in the female reproductive tract can survive 1-3 days, the egg can survive about 1 day after discharge, female ovulation time is about 14 days before the next menstrual flow, before and after ovulation a few days of sexual intercourse to have the possibility of conception. The woman’s ovulation time is about 14 days before her next menstrual period, and she has the possibility to conceive only when she has sexual intercourse in the days before and after ovulation. 4, the reproductive tract must be unobstructed. The male’s vas deferens must be open so that the sperm can be discharged. The female’s reproductive tract must also be open so that the sperm entering the vagina during intercourse can reach the fallopian tubes without any obstruction and meet the egg for fertilization. The fertilized egg can also enter the uterine cavity smoothly. 5. The environment inside the uterus must be suitable for the fertilized egg to be laid and develop. After fertilization, the egg develops while moving towards the uterus, arriving at the uterine cavity after 3-4 days, and then buried in the nutrient-rich endometrium for 6-8 days, and then continues to develop into a fetus. If the fertilized egg enters the uterine cavity earlier or later, the endometrium will not be suitable for the fertilized egg to settle and continue its development, and pregnancy will not be possible. If one of these conditions for conception is not present, infertility will result.