Embryo Project Encyclopedia Articles

In 2018, He Jiankui uploaded a series of videos to a YouTube channel titled “The He Lab” that detailed one of the first instances of a successful human birth after genome editing had been performed on an embryo using CRISPR-cas9. CRISPR-cas9 is a genome editing tool derived from bacteria that can be used to cut out and replace specific sequences of DNA. He genetically modified embryos at his lab in Shenzhen, China, to make them immune to contracting HIV through indirect perinatal transmission from their father, who was infected with the virus. HIV is a virus that attacks the immune cells of its host and weakens their ability to fight off diseases. At the time of He’s experiment, various treatments already existed at that could prevent the fetuses from contracting HIV without the need for gene surgery. Nonetheless, He’s experiment led to one of the first successful births of fetuses resulting from genetically modified embryos. He kept his experiment secret until he uploaded the videos announcing the birth of the fetuses, born as two twin girls. The experiment discussed in the videos was successful, but many scientists criticized the experiment due to ethical concerns with the way He conducted it.

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.

Stanley Paul Leibo studied the cryopreservation of embryos in the US in the twentieth century. Cryopreservation is a method of preserving biological material through freezing. Early in his career, Leibo collaborated with other scientists to study why cells were oftentimes injured during freezing. Later, Leibo and his team accomplished one of the first successful births using previously-frozen mammalian embryos. Leibo continued evolving simpler and more reliable methods of cryopreservation and embryo transfer for many different species over the course of his career, such as the development of a one-step procedure of transferring fertilized embryos between cattle. Leibo’s work to develop simple and reliable ways to cryopreserve cells and embryos enabled its use in a wider scope of research, including agriculture, reproductive medicine, and conservation.