Dyes illuminate live human embryogenesis

Assisted reproduction is on the rise globally. Cell morphology is commonly used for embryo selection, but the cell biology of early preimplantation development remains poorly understood. In this issue of Cell, Domingo-Muelas et al. reveal novel features of human embryos with critical implications for preimplantation genetic testing. Assisted reproduction is on the rise globally. Cell morphology is commonly used for embryo selection, but the cell biology of early pre-implantation development remains poorly understood. In this issue of Cell, Domingo-Muelas et al. reveal novel features of human embryos with critical implications for preimplantation genetic testing.