I would like to clarify that the key word here is constantly.
If it happens on and off, such as wanting it one day but not on others that's more in line with genderfluidity or genderflux, where it changes constantly. I want to bring this up because I know that lots of arguments about a person being transfem really tend to squash genderfluidity, typically out of ignorance but sometimes out of transmedicalist belief. Genderfluid people are real and valid, to the people who do it out of ignorance I hope this can be a learning experience to better understand genderfluidity, to people who are transmedicalists, fuck you, who do you think you are trying to decide whether people are valid or not, ~~if anyone isn't valid it's you~~ nvm too far.
Another key thing is that they actually have to want it, I'm adding this because I have seen in r/egg_irl where they try and get people to say it without meaning it, which doesn't make it so. The person has to really want it. Also extends to wanting to present feminine but not identifying as a woman, them wanting to act or present fem doesn't make them a woman, only identifying as one does.
TL;DR It's not as easy or Binary as it seems, every situation is a little bit different and it's important to remember that so one doesn't invalidate people by mistake when trying to help.