This is why important work on the topic by scientists like Kristina Olson is so important. While it's still very early, there are signs that well-managed transitioning doesn't cause harm. osf.io/preprints/ps...

But here again is why looking to cultures with long-standing traditions can inform how people meet similar challenges in the present day.

From Two Spirit to Bissu, Gender Diversity Has Deep Roots — How God Works

Around the world, gender diversity isn’t the exception; it’s fairly common. It’s also not a new invention.