Although cigarette smoking has been previously associated with impaired fertility in males, little was known of the effect of e-cigarette use on fertility. A new study recently published in the Journal of Human Reproduction confirms that daily use of e-cigarettes was associated with lower sperm counts. In this study, the authors utilized a population-based, cross-sectional design that included 2008 men (median age 19) who provided a semen and blood sample and filled out a questionnaire on lifestyle including information on smoking behavior. Compared to non-users, daily e-cigarette users had significantly lower total sperm count (147 million vs 91 million) as [...]