China is a big tobacco country, not only occupies the world’s largest tobacco production position, but also the world’s largest tobacco consumer, as well as the world’s largest tobacco victim countries. Medical research shows that smoking is one of the common risk factors for cardiovascular disease, cancer, chronic obstructive pulmonary disease and other diseases, while smoking can also lead to reduced male fertility, reduced sexual function, etc., seriously endangering the physical and mental health of men. For those men who are still struggling to prepare for pregnancy, they should pay enough attention to it. Long-term smokers ask: What are the effects of long-term smoking on the male reproductive system? Doctor’s answer: First, the sperm will be less energetic, less numerous, and more deformed, resulting in lower fertility. Cigarettes contain harmful substances that are absorbed into the blood circulation, and their long-term accumulation leads to a gradual increase in the concentration of harmful substances in the blood circulation, which interferes with the microcirculation of the testes and epididymis and the exchange of substances in the internal environment, affecting the development process of spermatogenic cells and changing the biochemical conditions necessary for the maturation of sperm in the epididymis, resulting in a decrease in the number of sperm and reduced motility. Some studies have shown that substances such as nicotine can directly affect spermatogenesis, and nicotine concentrations ≥1 mmol/L can significantly reduce sperm motility. Nicotine is also a co-oxidant for biological samples such as sperm, and can reduce male fertility by inducing membrane damage, interfering with the glutathione (GSH) metabolic cycle, altering sperm morphology, and inducing sperm DNA breakage. Smoke contains cadmium, and cadmium can cause sperm tail deformation, mitochondrial defects, etc., which increases the rate of sperm malformation. Second, it increases the rate of sperm DNA fragmentation, leading to bad pregnancy for the spouse. The DNA carried by sperm is the carrier that transmits paternal genetic characteristics to offspring, and if sperm DNA is severely damaged it will lead to infertility or abnormal offspring. Numerous studies have shown that smokers have increased levels of multiple peroxides in their seminal plasma and that oxidative damage can result in disruption of sperm DNA integrity and increased rates of DNA strand breakage and fragmentation. Some studies have shown that smoking can affect the function of the spindle during meiosis of germ cells, eventually leading to chromosomal abnormalities in sperm and an increase in aneuploidy, which can lead to the cessation of embryonic development in the spouse, spontaneous abortion or even offspring malformation or increase the risk of malignant tumors in the offspring. Third, the impact on sexual function, so that sexual desire decreased, erectile dysfunction. Testicular interstitial cells under the influence of harmful substances in cigarettes, its ability to synthesize the level of testosterone also decreased, the decline in testosterone will lead to a decrease in male libido; at the same time, cigarettes also lead to damage to the endothelial cells of the arteries, which in turn increases the carbon dioxide content of the blood, nitric oxide decreased, the blood flow to the penis decreased, so that the penis is hypoxic, and finally lead to erectile dysfunction. Therefore, male friends, to maintain a good sex life between couples, while maintaining a healthy physical condition and good fertility, should early abstinence or quit smoking habits, should not let smoking become a “stumbling block” in your fertility road.