Quoted from Kqed.com
UCSF’s Diane Ehrensaft, one of the leading proponents of socially transitioning transgender children, believes there is no minimum age, really, to pursue such a change.'For all of these interventions, our model is stages not ages,” she said. 'When a child is at the place in their life that they can get themselves in focus, help us see them, and are clear, consistent, and stable in both their representation of themselves, and also can express their desires of how they want to live their gender, that's the age.'We have seen some kids as young as two whose parents are bringing them in because they're beginning to say, ‘Me not boy. Me girl.’ Social transition can happen as soon as a child has language or the ability to communicate to us who they are.'