http://www.sciencedirect.com/science/article/pii/0047248480900512
It is a theory and probably not a very good one...............
Thank you.
That abstract implies that there is not a specific sexual dimorphism in teeth, but that tooth size is related to overall body size. And humans do show distinct size differences between males and females. That young man was probably smaller than average, leading to his initial misclassification as female.