stress is usually a cause of hermaphroditing, and I've heard genetics can be a factor as well. example, I helped a friend that I'm a caregiver for move a couple plants across town because our apartments were being inspected. so anyway, before we moved them they were starting to flower beautifully. a few days after we brought the plants back, we noticed pollen sacks developing on several of the plants. so yea, extreme fluctuations in temperate and humidity, as well as disruptions to the plants current light cycle can be very stressful on plants.