well, there are many possibilities, if the guppies were in fact molly babies, it has a slight chance of occurring, but i had the same thing happen with my long-tailed lizard, it had no male, got pregnant and layed eggs under the weirdest circumstances, so i have to say that is IS possible, or when u bought the molly it had already been mated and gotten pregnant. Another option would be divine intervention, but that would be 1 in a trillion, so i really hope this helps. Weird things happen.