Figure 2

Representation of the species for source of cells. Representation of the species for source of cells (by percentage) which (A) reported (n = 20 articles) and (B) did not report (n = 81) the sex of cells in 101 articles reviewed by the second search strategy. Some studies used cells from more than one species. (A) In studies that reported the sex of the cells, most used cells derived from rats, whereas (B) in studies that did not report sex, most cells were derived from humans.