The Decades Long Process of Making a Viable Egg Cell

 This week's episode is a bit of a prequel focused on the making of the egg, which will make the embryo. Sorry guys. The sperm is an NPC in this one.  Why do we care? Because we might not even think about how eggs are made. Until circumstances require it often in the form of a miscarriage, miscarriage rates on average are pretty high.Something like one in four suspected,  and that's just of the embryos that actually get implanted. An estimated 60% of embryos never make it past. The sensors in the uterine lining. Miscarriages tend to congregate around the first trimester. Something like 80% of them happen then. And the largest fraction of those is seemingly related to aneuploidy.When cells that make up the embryo have the wrong number of chromosomes. So the question is. How does it work, when it works, and what happens when it goes wrong?