Let's talk about sex in the context of COVID-19.

In recent months, the coronavirus disease 2019 (COVID-19) pandemic has sent many countries into crisis. Studies have shown that this virus causes worse outcomes and a higher mortality in men than in women. It has been recognized that sex can affect the immune response to a pathogenic agent, as well as the susceptibility for some respiratory diseases. These different responses in males and females may be related to the actions of sex hormones. Angiotensin-converting enzyme 2 (ACE2) acts as the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19. The expression of ACE2 is influenced by sex hormones; therefore, we discuss in this article that this could be one of the reasons why COVID-19 is more prevalent in men than in women.