Raising the bar for human post-implantation embryo models

The generation of stem-cell-based embryo models has ushered in a new era for human embryology, but improving their reproducibility and lineage fidelity has remained a challenge. In this issue of Cell Stem Cell, Chen et al.¹ and Oura et al.² develop refined strategies to assemble human post-implantation embryo models with greater accuracy and efficiency, setting a new standard for the field.