Causes of ınfertility in Men 182 / 5000 The most common cause of infertility in men is a decrease in sperm count and / or motility and / or malformations (oligo-asteno-teratospermi-OAT). The reason is often unclear. Surgical treatment of varicocele with OAT is generally recommended by urologists, but its efficacy has not been established. If the number of motile sperm…