I heard, once, that it was very occasionally seen in chickens; that you might find a fertilized egg from a hen in a facility which had no roosters. Don't know whether that is true, or whether it would produce a viable chick, but I thought it was interesting anyway. I think I was in high school or thereabouts.
It sort of coincided with the time that I was trying to sort out whether I was really supposed to believe Bible stories, since I had always sort of lumped them together with fairytales & mythology in my mind as a kid, and was finding the realization that adults took them as absolute truth somewhat perplexing. The idea that maybe once in many billion there might be a scientific reason a virgin could conceive appealed to me on that level.