Fertility in men is directly related to sperm quality. This is also the reason why one of the first tests that are prescribed for difficulties with conception is the spermogram. The sperm production cycle is long, so many factors can affect sperm quality. Duration averages within 100 days. This period includes about 75 days for the cells in the testicles to divide and develop; 20 days to travel through the epididymis and about 5 days to travel through the vas deferens. During these approximately 100 days, the sperm is vulnerable to both its immediate environment and diet, work regimen, and more. Work and contact with toxic substances, pesticides, chemicals, ethylene oxide, vinyl chloride, heavy metals, lead, cadmium, mercury, radioactive elements, X-rays, as well as various other pollutants have a direct impact on sperm development. Smoking, excessive use of alcohol, coffee, stimulants and drugs have a serious impact. They have been shown to directly damage the cells from which the sperm originates (spermogonia). Nicotine and tars have a detrimental effect on the fertilizing qualities of sperm, mainly on sperm concentration, motility and morphology. To this we can add that smoking is associated with poor sperm function in a penetration test, as well as leading to an increase in leukocytes in the ejaculate. Prolonged driving and cycling, wearing tight pants and briefs (instead of boxer shorts), hot baths, showers and saunas, as well as any exposure of the genitals to high temperature, lead to an increase in testicular temperature. In turn, heat greatly disrupts the process of division and maturation of gametes. Unfavorable factors include fatigue, mental strain, sedentary lifestyle, overweight, unhealthy diet, long-term computer work, and stress. Parents of boys with retained testicles in the abdominal cavity can wait up to a year after the child’s birth, but in case the testicles do not descend into the scrotum after that, medical intervention is necessary. Operations for inguinal hernia, dilated veins of the testicle (varicocele) are also related to sterility. Even 2 degrees higher temperature can have a bad effect on sperm formation. Their concentration will drop, the number of healthy ones decreases, and the number of damaged ones increases. In the summer, the concentration of sperm naturally decreases. Thus, the sperm count in the ejaculate can drop from 320 million to 250 million. A warm bath (43-45 degrees) for half an hour a day does not significantly reduce sperm concentration. Tight-fitting briefs, sports shorts or pants have the same effect.