Ok, I'm going to pull this out of my ass because I have no way to prove it, but I think no gender has been "invented" lately, rather discovered (just as the Bolzano theorem existed before Bolzano). They're just recently been described because they were previously repressed with different kinds of violence. Or maybe at some point in history for some society, just ignored. That doesn't mean there wasn't people all along history that felt or identified themselves in the same way that some current people that may now use a new term to express it. If some modern person had known those ancient people, they would describe them with one of the "new" genders.
Or the more you believe in it, the more likely you are to believe in it working. You can believe some really improbable stuff happens when you open yourself to believe in that possibility.
You are right that the reading compromises the credibility of the hypnosis, but I'm sure if you have faith in any, your faith will cross that
