Dr. Nicolas Rivron is a Principal Investigator at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences in Vienna. His group recreates embryonic development using mammalian stem cells in a dish to better understand the encoded principles of self-organization. He talks about building human blastoid models and using them to study implantation. He also discusses differences in development between mice and humans, trophectoderm stem cells, and an ethical framework for embryo models.