My neighbor, Karen Phillips, adopted two cats, sister and brother from the same litter. They’ve been growing in leaps and bounds and she decided it was time to have Wiley, the male fixed. When she returned with Wiley, his sister would have nothing to do with him in his altered state. She hissed at him and swatted him away from her. She hissed him away from the water dish and food, “No, no, no! You are useless to me now”, she seemed to say.
Karen determined that her female is probably pregnant at four months old… by brother Wiley. I guess that is what you call Sex in the Country.