The hazards of smoking for men in preparation for pregnancy are manifested in the following ways: affecting fertility, increasing the rate of sperm deformities, and increasing the rate of fetal malformations. 1. Impact on fertility: cigarettes contain more harmful substances, long-term, large quantities of smoking may inhibit the activity of sperm, resulting in reduced sperm activity, affecting fertility. 2. High sperm deformity rate: cigarettes contain nicotine, which may affect the development of sperm and increase the sperm deformity rate. 3. Increased fetal deformity rate: When the deformity rate of sperm increases, the combination of sperm and egg will also increase the deformity rate of the fetus. During the preparation for pregnancy, it is recommended that both men and women avoid smoking, and also need to maintain good habits, not drink alcohol, supplement nutrients, and do a good job of pre-pregnancy checkups, which will be beneficial to improving the chances of pregnancy and the health of the fetus after pregnancy.