You have to be a totally blind fool to not be able to tell that the “girl” is actually a guy ... the length and structure of the fingers, and the size and shape of the feet are a dead giveaway, as is the jaw, the larynx, the shape of the eyes ... You have to be just plain stupid - or else drunk to the point of stupor - to not know.
It can be very difficult to tell. The best clues are voice and height - most Southeast Asian women are very short. If “she” is 5’7” with a raspy voice and a drop-dead perfect face and body...keep looking. :)