Janet Rossant is president of the Gairdner Foundation, and senior scientist emeritus at The Hospital for Sick Children, University of Toronto, Toronto, Canada. The first few weeks of a human embryo’s ...

The schematic depicts five stages of human implantation: (1) blastocyst differentiation into ICM/TE; (2) apposition and adhesion to luminal epithelium (dependent on L-selectin/ligand); (3) invasion ...