Oxidative stress has long been known to be associated with reproductive health disorders in men. It leads to reduced sperm motility and damage to their genetic information. This causes an increased risk of repeated abortions due to fertilization disorders and genetic abnormalities. The generation of free radicals is a natural process and is necessary for reproductive health, but their accumulation leads to disturbances in fertility, the proper course of pregnancy and the genetic health of newborns. Infertility is defined as the inability to conceive after 1 year of regular intercourse without the use of protection. One of the mechanisms that lead to idiopathic male infertility is oxidative stress. Other factors also affect male reproductive health. Such are varicocele, cryptorchidism, hypogonadism and genetic causes. The increased synthesis of free radicals, combined with decreased antioxidant activity, leads to an imbalance in oxidative processes, decreased sperm motility and increased damage to their DNA. They are significantly susceptible to the harmful effects of free radicals because they contain high amounts of unsaturated acids in their cell membranes. Free radicals accelerate lipid peroxidation processes, which leads to increased levels of oxidative processes in the cell. This leads to a violation of the integrity of the sperm membrane, an increase in its permeability, a change in the motility of male germ cells and the induction of programmed cell death. It is believed that one of the causes of varicocele is the increased level of oxidative processes, which leads to damage to the DNA of the spermatozoa, as well as the increased temperature in the scrotum. It, in turn, also increases the production of free radicals and has a negative impact on the quality of the seminal fluid. High levels of free radicals are also associated with an increased risk of infections of the male genital organs – urethra, prostate, seminal vesicles, epididymis, vas deferens or testicles. This is due to the capacity of seminal leukocytes to produce higher amounts of free radicals than all other cells with an aerobic metabolism. Infections are also associated with increased levels of oxidative stress. Also, high blood sugar levels – hyperglycemia is also a key factor in male infertility. A significant association between prediabetes and diabetes has been established with increased production of free radicals, which impairs seminal fluid quality. References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6472207/