In an alternate universe where all humans were female, what do you propose would be the best/most believe-able method of procreation? Are there any animals in the world who's breeding methods would be suitable? I'm planning on writing a book based on this alternate reality and I'm not sure how to explain how babies would ever made..
Unless you’re using a very high tech scenario (advanced reproductive technologies can create viable embryos from two genetically female parents) what you are looking for is parthenogenesis.
Parthenogenesis is a natural process in some species, mostly arthropods and some reptiles like a whiptail lizards species. That said, some individuals of normally sexual species occasionally display parthenogenesis, usually in captive situations when a male has been unavailable for some time. Reptiles, amphibians and sharks have displayed this ability with success. Birds have been reported laying parthenogenic eggs, but they didn’t mature to hatching.
There are a lot of technical concerns that would need to be addressed or hand-waved for your world. I touched on the idea briefly of parthenogenic induced ovulators in the Medusa post, but you also need a mechanism or trigger to set off the parthenogenesis, otherwise there is nothing stopping your all female species from being pregnant all the time, which is jolly inconvenient.
It does mean that all females become genetic clones of each other, as there’s no method for mixing genetics, which means the population is vulnerable to viral outbreaks and can no longer evolve.
