The necessary conditions for boys and girls to get pregnant (carry a child to term) are related to normal sex life, normal sperm, regular ovulation, clear fallopian tubes, normal uterus and so on. 1. Normal sex life: regular sex life is needed, too much or too little sex will affect the quality of sperm. 2. Normal sperm: men should have normal sperm such as sperm density, mobility and penetration. 3. Regular ovulation: it means that the female ovary functions normally, has a cycle of mature eggs and regularly discharged. 4. Smooth fallopian tubes: the fallopian tubes are the channels through which sperm and eggs meet, and the smoothness of the tubes is a necessary condition to ensure the combination of sperm and eggs. 5. Normal uterus: the shape of the uterine cavity is inverted triangle, the uterus is normal development and no disease, in order to facilitate the fertilization of the egg bed. Before men and women to prepare for pregnancy, it is recommended to do a good job of pre-pregnancy preparation under the guidance of a professional doctor to ensure eugenics.