Gonzalez DC, Nassau DE, Khodamoradi K, et al. - Researchers evaluated sperm parameters before and after mRNA vaccine administration because reproductive toxicity was not evaluated in the clinical trials and SARS-CoV-2 has been associated with decreases in sperm parameters. It demonstrates that two mRNA vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna), received Emergency Use Authorization from the US Food and Drug Administration. Only 56% of individuals in the US reported wanting to receive the vaccine, despite high efficacy and few adverse events found in clinical trials. In addition, one of the reasons for vaccine hesitancy is the potential negative effect on fertility.