In 2007, Françoise Baylis and Jason Scott Robert published “Part-Human Chimeras: Worrying the Facts, Probing the Ethics” in The American Journal of Bioethics. Within their article, hereafter “Part-Human Chimeras,” the authors offer corrections on “Thinking About the Human Neuron Mouse,” a report published in The American Journal of Bioethics in 2007 by Henry Greely, Mildred K. Cho, Linda F. Hogle, and Debra M. Satz, which discussed the debate on the ethics of creating part-human chimeras. Chimeras are organisms that contain two or more genetically distinct cell lines. Both publications discuss chimeras with DNA from different species, specifically in response to studies in which scientists injected human brain cells into mice. “Part-Human Chimeras,” contributes to a chain of ethical and scientific discussion that occurred in the mid-2000s on whether people should be able to conduct research on chimeras, especially in embryos.

In 2006, bioethicist Jason Scott Robert published “The Science and Ethics of Making Part-Human Animals in Stem Cell Biology” in The FASEB Journal. There, he reviews the scientific and ethical justifications and restrictions on creating part-human animals. Robert describes part-human animals, otherwise known as chimeras, as those resulting from the intentional combination of human and nonhuman cells, tissues, or organs at any stage of development. He specifically criticizes restrictions against creating part-human animals made by the National Academy of Sciences, or NAS, in 2005, arguing that while they ensure that such research is morally justifiable, they might limit scientists from conducting useful science using part-human animals or entities. Robert challenges the moral rationales behind prohibiting chimera research, arguing that they may impede scientists from conducting research that could have important benefits to biology and medicine, and suggests how to balance the conflicting moral and scientific needs of such science.

Alan Osborne Trounson is a scientist from Australia who studies embryology and stem cells. His research has improved the success rates of in vitro fertilization, or IVF. IVF is a medical procedure in which scientists fertilize an egg cell with sperm outside of the body, often in a laboratory petri dish, then transfer the fertilized egg to a woman’s uterus to start pregnancy. Trounson also researched embryonic stem cells, or stem cells collected from embryos, and their potential for treating injuries and diseases. Additionally, Trounson led the Californian Institute for Regenerative Medicine, or CIRM, one of the largest agencies to fund stem cell research in California, from 2007 to 2014. Over the course of his career, Trounson developed several techniques that improved the effectiveness of IVF, including fertility treatments and cryopreservation, and supported stem cell research as a scientist and administrator.