I ask this question from the research for Fire of Man and since I also asked myself the question how to understand if a girl is a lesbian several times, here we are, let’s see if it is possible and how to do it.
I think that in 50% of cases it is not easy, but easier to identify a girl attracted by her own sex.
In the other 50% of situations it is not impossible, but really difficult to identify if the girl prefers a man or a woman.