A new study suggests that, among men, low testosterone levels in the blood are linked to more severe COVID-19. The study contradicts widespread assumptions that higher testosterone may explain why men, on average, develop more severe COVID-19 than women do. “The groups of men who were getting sicker were known to have lower testosterone across the board.” Throughout the pandemic, doctors have seen evidence that men with COVID-19 fare worse, on average, than women with the infection. One theory is that hormonal differences between men and women may make men more susceptible to severe disease. And since men have much more testosterone than women, some scientists have speculated that high levels of testosterone may be to blame.