An eight-cell human embryo, three days after fertilizationWIKIMEDIA, EKEM: RWJMS IVF PROGRAMGiven advances in synthetic biology, researchers can now use stem cells to create human tissues, organs, and other approximations of early developmental structures. These recent innovations also raise ethical questions that may not be adequately answered by the self-imposed 14-day rule that has governed research on embryos for decades. That rule prohibits experiments using embryos older than two weeks post-fertilization, and resulted from the facts that researchers could only keep embryos alive for 14 days in the lab and that, after 14 days, embryos begin to develop the rudiments of a nervous system.
Now, Harvard scientists who pioneered some of the advances that allow for the creation of what they’ve dubbed synthetic human entities with embryo-like features (SHEEFs), are calling for a rethink of the 14-day rule. Embryoids are balls of pluripotent stem cells that begin to resemble embryos.
“Here we argue that these and related experiments raise more foundational issues that cannot be fixed by adjusting the 14-day rule, because the framework underlying the rule cannot adequately describe the ways by which synthetic human entities with embryo-like features (SHEEFs) might develop morally concerning features through altered forms of development,” the researchers wrote in an article published in eLife yesterday (March 21). “We propose that limits on research with SHEEFs be based as directly as possible on the ...
