I can't imagine where you're getting your information and assumptions. My child grew into the ability to express the gender(s) they had experienced through their life (now late 30s), and is fortunate to live in a state where that expression (and all others, including yours) is protected by law and health insurance supports their medical and surgical transition. They're working on the legal transition to their chosen name and gender marker.
With @notpickard I'm glad you're willing to allow people to use their restroom of choice, but the gender dysphoria we have, wittingly or not, imposed on numbers, however small, of our kindred is no insignificant matter. It costs lives, from inside and out. Please address your hopeful energy, not to people "growing out of it," but to our society growing out of making gender determinative for so many factors of our lives.