Possible reason: Generally, females are more resistant to infection than men, and this is possibly mediated by several factors including sex hormones and high expression of coronavirus receptors (ACE2) in male, and also life style, such as higher levels of smoking and drinking among men as compared to women [32], this imbalance supports a higher susceptibility of men to develop severe respiratory diseases following COVID-19 infection. This evidence concerns the gene ACE2 and infection.