Children as young as two or three often have a clear sense of their own gender. While it affects a small percentage – one in ten thousand males and one in forty thousand females – some individuals experience a disconnect between their assigned sex and their inner sense of self. Signs of this can emerge very early. The families featured in this documentary all share a similar experience: their children have consistently and strongly asserted, almost from the start of speech, that they identify with the opposite gender of their body.