The point is that sight can be defined, even to a blind person. Under today's lingo, gender can't. Adrenaline increasing just means that someone is feeling stress.

I mean, I don't think people can even describe gender in poetic/emotional terms. What exactly is the "feeling" of gender? What does being a woman feel like? What does being a man feel like?

I have no idea what people are talking about when they say they feel like a different gender. There's no test that can be done to detect gender and it cannot be defined scientifically. What's more, people are saying that they feel some sensation that is indescribable and totally alien to my experience of being human.

Today's definition of gender makes just as much sense to me as someone who says that they feel like a wolf or a lion.