Bbc Inside Science

One of the most fundamental developmental stages we humans go through is extremely poorly understood. The first few days of the embryo, once it's been implanted in the womb is incredibly hard to study. Yet it's the time when the majority of pregnancies fail. Professor Magdalena Zernika-Goetz at Cambridge University is a leader in the field of making 'model embryos' in both mice and humans. Model embryos until now have been grown in the lab from donated fertilised eggs, but these are hard to come by and governed by strict laws and ethical guidelines. Now researchers in the University of Michigan have used human pluripotent stem cell lines (originally isolated from embryos, but kept and nurtured as clumps of dividing cells in petri-dishes for many years) to make a model embryo that has shown signs of development and organisation in the crucial 7-10 day window. Magdalena and Gaia Vince discuss how helpful these will be to understanding crucial early stage pregnancies and as a tool to test drugs, treatments and d