Earlier this month, two papers were published (from the Brivanlou and Zernicka-Goetz labs) that reported in vitro systems to study development of the human embryo through implantation stages. These experiments have kept human embryos developing for longer than any previous work, and close in on the 14-day limit imposed by many governmental and regulatory bodies. 14 days were set as a limit (at a time when it was technically impossible to keep embryos alive this long) because this is the stage at which the primitive streak emerges – the time at which embryos can no longer split or fuse – and has been considered by some to be the stage at which a ‘morally significant individual’ comes into being (see this discussion in Nature). But now that we can culture human embryos up to this point, is this 14-day rule still appropriate? Would it be ethically ‘wrong’ to try and study human gastrulation in culture, or do the potential advances in our understanding of human development (along with their possible therapeutic implications) outweigh any ethical concerns involved? This month we are asking:
Should the 14 day limit on human embryo culture remain in place, or should it be extended or even dropped?
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