Transplants of hESCs into blastocyst-stage mouse embryos have been performed to see if the chimeras could provide “an accessible platform for studying the emergence of many human cell types; and with the expansion of available hESCs to include genetically diseased lines, mouse/human chimeras may allow us to elucidate the bases of disease by examining the behavior of such hESC lines in live animal models” (James et al. 2006, 100).