Learning about human development from clinical IVF data

The early human embryo is the physicist's dream for studying development. Between fertilization and implantation in the uterus, mammalian embryos undergo a global reorganization (compaction) followed by a symmetry-breaking differentiation (blastocyst formation), with no external direction from the mother. But for ethical reasons, we cannot do experiments with human embryos. So how can we understand human development without experiments? Here, we examine tens of thousands of videos of human embryos recorded during routine clinical IVF procedures. We use those videos to explore the natural variability in mammalian preimplantation embryo development, and we leverage this variability to identify critical factors in early development.