Note that human embryos had been grown before, however, until the period of seven days. Further multicellular ball" was transplanted into the mother's body the recipient. By the method of cultivation of this period has been extended 13 days to increase the chance of successful implantation of the embryo.
"This is the most mysterious stage of human development," says Magdalena Zernicka-Goetz, Professor, University of Cambridge.
Experiments for the further cultivation of embryos in vitro is not yet possible. Under U.S. law, it is impossible to conduct research with human embryos older than 14 days. While a number of approvals will not be obtained, experimental medicine in this field will stand still. "The process of implantation is still a big mystery for doctors," believes Ali Brivanlou, author of the study from the Rockefeller University.