A new study in the journal Reproduction shows that COVID-19 may negatively affect sperm quality and reduce fertility in men. Researchers studied 84 men with COVID-19 infections, all but one of whom had either moderate, severe or critical forms of the disease. The impact on male fertility seemed to depend on the severity of disease. Fortunately, these effects tended to improve over time. Exactly how and why COVID-19 affects sperm quality and male fertility is unclear, although it could be related to changes in the immune response. It’s also possible that therapies for COVID-19 may have harmful consequences for male fertility.