I'm guessing your growing with bag seed, most likely the plant your seed is from was stressed because of half assed growers or just lack of good grow conditions. All of the seeds you get from this plant will be feminized, but will have the same changes if not higher of self pollinating and producing seed. Female flowers know that their life is ending and if they have not been "knocked up" by a male they will do it themselves as survival is the goal of anything living