In a study of sex differentials in COVID-19 patients, Asghar et al. arguments for these variations include the following: women ́s immune cells activate more than men, women produce lower levels of interleukin-6 (IL-6) compared to men, which is associated with better longevity; different levels of angiotensin converting enzyme-2 (ACE2) in men and women, the effects of testosterone on ACE2 levels and the fact that the ACE2 gene is located on the X-chromosome. This evidence concerns the gene ACE2 and COVID-19.