You've probably heard of parthenogenesis. Some female animals can produce offspring without having any eggs fertilized. But did you know that humans have found ways to induce parthenogenesis for hundreds of years?
As with a lot of scientific discoveries, the induction of parthenogenesis came out of a deep-seated economic interest. In the 1800s, silk was a precious commodity, but silk worms were temperamental little critters. Any breakthroughs as to their care and keeping might have tremendous economic advantage. So people did anything, like rubbing unfertilized eggs with brushes, or dipping them in sulfuric acid. Amazingly, this seemed to do them good. They began developing just like normal, fertilized eggs, and the resulting larvae seemed normal.
This was a revelation. While occasional parthenogenesis was known, it was known to happen in creatures naturally. Suddenly it looked like pure chemistry could trump the necessity of having two progenitors. Scientists all over the world started looking into how to make life of their own. Starfish, sea urchins, and eventually frogs, were all eventually developed with one biological parent and one purely chemical parent.
There were two main problems that most people faced. The first was how to make the egg develop a tough membrane - the way it does when it's first penetrated by a sperm cell. The second was to keep the unfertilized egg from simply disintegrating afterwards. The amount of trouble one went to in order do this increased as the experiments shifted from insects and sea creatures to vertebrates. Silk worms just needed a quick exposure to acid. Sea urchins and starfish tended to need brushes with either acid or base for different amounts of time, after which they needed to be in oxygenated salt water. Some developed when only exposed to hypertonic water. Hypertonic water has a higher than normal amount of dissolved substances in it. This affects the osmosis of the cell, since water will naturally rush across a barrier from low to high concentrations of solutes. Frogs eggs, in the early days, didn't develop purely from chemistry. They required a needle and a tiny fragment of blood. If this sounds like cheating, the blood didn't have to be from a frog. It could be from a fish or a newt, and the cells would still develop.
Today, there isn't too much call for continuing induced parthenogenesis. Still, we are finding more and more creatures, from bees to lizards and snakes, can engage in parthenogenesis. This could mean that we would be able to induce a "virgin birth" in many of the creatures of the world.