Figure 3.

Sex of nonhuman mammals reported in angiotensin-converting enzyme 2 (ACE2) publications over the past two decades. Shown is the proportion of original research articles on nonhuman mammalian primary cells, tissues or whole animals that are conducted in male only, female only, both sexes or studies in which the sex is unknown (i.e., not reported) as a function of the total number of articles as a pie chart (A) or number of articles published each year since ACE2 was discovered (B).