So many stories! I have the brain/spirit/soul/heart of a woman, I am really a woman, provoking research into psychology and brain physiology, and legal or social responses. I don’t care whether it is true or not, but how it liberates or constrains us. Does it permit you to do what you want to do? Does it prevent you? How does it affect others’ resentment or tolerance of you?
It would be lovely to be able to say, with scientific precision, “I am a woman”, because that would make everything simple. Of course transition would be right, and I would be allowed in women’s spaces. Of course society and the law would treat me as a woman, and anyone who dissented would be clearly wrong. I can’t do that because it is not so. The concept of “woman” is not so clearly divided from that of “man” as the transphobes would think, but useful scientific definitions relating to reproduction call me clearly a man. What I am left with is a social or cultural concept, so I say “I am a woman” according to the modern English definition of the word, which includes trans women. This liberates me to transition, and to argue that others should accept me, but that is a circular argument- I am a woman, because people call me a woman.
If a transphobe argues that I am not a woman because I have a Y chromosome and any scientific wiggle-room about intersex people does not apply to me, the question is Why. It could be because they want to enforce Complementarian “biblical” gender roles, or because they want to direct feminist energy against me, calling me part of the Patriarchal Oppression of Women.
If you are deciding whether to transition or not, this is good and bad news. The bad news is that you will never be able to state with complete certainty that you are a woman, and therefore must transition. You have to find what you feel. What do you want? Will transition make you happy? The good news is that if you really want to transition, nothing should stop you. If you want to transition, you are trans. No-one can tell you not to transition because you are not trans. There are unscientific, cultural stories around arguing that you are not, such as “Autogynephilia”, but do not worry. It is a myth. “Female embodiment fantasies” explains the phenomenon far better.
It also widens your options. No, you are not objectively, scientifically a “woman” but you have particular characteristics, desires and needs which make you desire transition. Are there alternatives which might make you happy with less effort?
It means that you will never convince the transphobes. You cannot point to objective scientific evidence that you should be able to use women’s changing rooms. However, the people who really care and want to stop you are a small minority. Most people don’t see what the fuss is about, and so those who do care are desperate to convince them. But the more they exaggerate the threat of trans women in women’s loos, the more reasonable people they drive away.