Purpose: The effects of smoking on testicular function and sperm physiology were studied.
Materials and methods: Left testicular biopsy was performed in 49 smokers and 28 nonsmokers. Seminal specimens from these men were analyzed.
Results: Testosterone levels in the left testicular vein, left testicular androgen-binding protein secretion rate (in vitro), sperm motility, percentage of morphologically normal spermatozoa, sperm morphometric parameters and outcome of sperm function tests were significantly lower (p < 0.05) in smokers than in nonsmokers.
Conclusions: Morphological sperm abnormalities due to secretory dysfunction of the Leydig and Sertoli cells may be the cause of impaired sperm fertilizing capacity in smokers.