Developmental biologist Lewis Wolpert is credited with saying, “It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life.” Gastrulation, simply put, means the embryo develops an axis and distinctly different cell layers. In the human embryo, gastrulation takes place during the third week post-fertilization. Formation of endoderm occurs over days 14-15, and the mesoderm begins to appear on day 16 (see Figure 1-11 here). Ali Brivanlou, of New York’s Rockefeller University, identifies gastrulation, or the breaking of symmetry in the embryo, as the “major Holy Grail of developmental biology.”
Why is this so? During the third week after conception, the embryo has burrowed into the mother’s womb, and the peering eyes of scientists cannot visualize the events there. With the 14-day rule in place regarding embryo research, laws or guidelines in various locales outlaw or discourage (as in, do not fund) laboratory culturing of embryos beyond that point. So, Brivanlou’s lab “came up with a model of human embryos that is developed outside of the womb and is not the product of sperm and eggs, but the product of human embryonic stem cells that self-organize into complicated structures.” These embryonic stem cells have formed what appears to be an embryo, but in Brivanlou’s terms, “could never become a baby.”
Dehumanizing the embryo is one of the essential components of making research on embryonic humans more palatable to the public. It will also be en essential step in a workaround of the 14-day rule. It appears that “model embryo” will join other terms such as “embryoids,” “gastruloids,” and “SHEEFs” as some element of humanity that scientists do not recognize as humans worthy of legal protection. Regarding Brivanlou’s “model embryo,” Harvard Medical School’s Dean George Daley calls it a “remarkable tool in a petri dish.” The “tool” with which Brivanlou and others concern themselves is both human and alive; otherwise, would they be interested?
Let’s think about this, using an analogue. If well-trained scientists could produce men and women without chests, what would be allowed? Would they have to call such men and women without chests “human”? Could they use men and women without chests for experiments? Would the experiments have to be approved by institutional review boards? Would the rest of us pay the scientists – handsomely – to do this? Could they win prizes?