Smoking is often thought to be associated only with lung cancer, emphysema and cardiovascular disease, and is rarely associated with fertility. The chemicals in nicotine and tobacco tar enter the semen when it enters the bloodstream, and there is no question that smoking affects the quality of spermatozoa. Studies have found that smokers have lower sperm counts and lower sperm motility than non-smokers, and smokers also have a higher number of sperm abnormalities. Heavy smokers had significantly higher rates of sperm DNA fragmentation compared to non-smokers. Sperm chromatin structural integrity is very important for fertilization and subsequent embryonic development, and sperm DNA damage such as DNA fragmentation, chromatin assembly abnormalities, and ichthyoglobin defects to a certain extent can lead to a decreased pregnancy rate and affect embryonic development. Therefore, it is clear to assume that smoking can have an impact on male fertility and quitting smoking is a must especially for men with low fertility. Smoking also affects erectile dysfunction, which for some people, especially young people, is a more serious problem than cardiovascular disease. Sperm quality improves immediately after quitting smoking; however, cardiovascular disease and erectile dysfunction do not recover as quickly as sperm quality. In addition, erectile dysfunction itself is a sign of insufficient fertility.