Human development starts from a single fertilized oocyte that has the potential to develop into both foetal and extraembryonic tissues. After fertilisation and during the next few cell divisions ...

A stem-cell derived human ... tells me. Embryo research is legally, ethically and technically fraught. But there is now a rapidly developing field mimicking natural embryo development.

gastrulation (around day 18 of human embryonic development, day 7.5-8 of pregnancy for rabbits and mice). (credit: Richard CV ...