Smoking is responsible for a large number of medical disorders, and is a common and preventable cause of many diseases. Recent experiments have been conducted to study the causal link between smoking and impaired fertility in men, and it was found that a large number of harmful particles are transferred through smoking fumes to the testis, and they end up damaging the sperm, which results in impeding many of the characteristics of the sperm and the ability to have children. The sperm damages the DNA of the sperm, which leads to a deterioration in functions and a significant decrease in the ability of the sperm to fertilize. In addition, DNA abnormalities caused by smoking may be genetically transmitted to the children of smokers. Some reports prove that smoking leads to a decrease in testosterone levels, which increases its negative effects on fertility.