Time matters: Human blastoids resemble the sequence of blastocyst development.

In a recent issue of Nature, Kagawa et al. reported a highly efficient and robust protocol for generating human blastoids from naive human pluripotent stem cells. The blastoids resemble human blastocysts, follow the sequential lineage specification of blastocyst development, and can attach to endometrial cells with the polar trophectoderm to model implantation.
Competing Interests: Declaration of interests Juan Carlos Izpisua Belmonte is a member of the Cell Advisory Board.
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