What factor can impair spermatogenesis in men?

Spermatogenesis, the process of sperm production, is highly sensitive to environmental conditions, and the temperature of the testes plays a crucial role in this process. The testes are located in the scrotum, which provides a cooler environment than the rest of the body, essential for optimal sperm development. When the testes are overheated, it can result in reduced sperm production and abnormal sperm development, leading to fertility issues. This overheating can occur due to various factors, such as prolonged exposure to high temperatures, tight clothing, or saunas.

Other options while relevant to male reproductive health, do not directly impair spermatogenesis. For instance, ligation of the vas deferens affects the transport of sperm but does not impact the production of sperm itself. Similarly, an enlarged prostate gland may have implications for urinary function and sexual health but does not directly impair the sperm production process. Segmented flagella, on the other hand, would pertain to sperm motility rather than their production. Hence, overheating of the testes is the most significant factor among the options for impairing spermatogenesis.