As we get closer to being able to grow human eggs from stem cells, it’s important to be sure that the eggs are high quality and safe enough to use for reproduction.1 So, let’s discuss: what does an egg need to have in order to develop into a healthy baby after fertilization? How can we tell if an egg is good or not? And what does this mean for in vitro oogenesis?Good geneticsAt the most basic level, an egg must have the correct number of chromosomes. Chromosome pairing is established during meio...