Generally speaking, 21-29 years old is the best age for women to have children, while 23-30 years old is the best age for men to have children. This is because if a woman is younger than 18 years old to have a child, at this time the body’s organs are not yet mature, which is not conducive to pregnancy; if she is older than 35 years old to have a child, not only will the risk factors increase, but also prone to cause obstructed labor or other complications, and the risk rate of chromosomal disorders in the fetus will also increase. A woman of 21 years old is not only mature in gonadal function, but also in psychology, so she can bear the pressure of pregnancy and labor, so 21-29 years old is the best age for women to give birth to a child. For men, if they are too old, not only will their sperm activity decrease, but also the incidence of fetal diseases, such as sperm abnormalities, will increase. For both men and women, having children too early or too late is not too appropriate, and it is best to get married at the most appropriate age. Couples preparing for pregnancy are advised to go to the hospital for a pre-pregnancy eugenic health checkup to assess whether their bodies are suitable for pregnancy; quit smoking and drinking, develop good living habits to keep their bodies healthy, avoid prolonged exposure to environments that are radioactive or polluted, and get out of toxic and hazardous work environments. Women should start taking oral folic acid three months before the planned pregnancy to prevent neural tube defects.