Consider the possibility that once the planet was populated only by species reproducing asexually. The Y chromosome was absent. Along comes an alien pathogen that infects the indigenous species, introducing the Y chromosome into their DNA. This parasite creates the male of each species and changes the course of evolutionary history. It is bery successful since for a species to persist and proliferate, it must propagate the Y chromosome with a probability of 50%. What circumstancial evidence might support this wild theory? What are the implications?
Disclaimer. The above is FICTION and SPECULATION. It’s just an intellect exercise, a what if, thought experiment.