This article is a commentary on a study published in the journal Hum Reprod 2003;18:1055-61. The aim of this study is to assess the impact of continuous exposure to traffic pollution on sperm characteristics and the presence of metabolites in the blood, compared to an unexposed population living in the same geographic area. The results obtained are interesting; indeed, it appears that prolonged exposure to traffic pollution has an impact on sperm characteristics, without affecting pregnancy rates. However, the influence of exposure duration on sperm characteristics was not analyzed. Furthermore, changes in sperm quality due to the subject’s aging must, in this case, be factored into the statistical analysis, and age was unfortunately not used as a confounding variable. It would therefore be worthwhile to repeat this study, focusing only on couples of reproductive age, and to conduct a longitudinal follow-up to better understand the impact of road traffic pollution on sperm characteristics and pregnancy outcomes.