That study might be the most flawed I've ever seen. It relied on parents' perceptions like you said. And the author selected for parents who refused to accept their children coming out as trans. Among other problems.[1]

[1] https://www.youtube.com/watch?v=pnc_KvWkiHw&t=3324s

Wow. You're right that's an amazingly badly constructed study. Low-n, indirect-non-patient self-report (parental reporting/perception bias) w/ no cross adjustment or multi-party correction. Biased recruitment practices... hecking YIKES.

Oh, and of course, the methodology was soundly criticised and contextualised in the same journal; imagine that. - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6424477/

> The level of evidence produced by the Dr. Littman’s study cannot generate a new diagnostic criterion relative to the time of presentation of the demands of medical and social gender affirmation.

Surprise.

Worth noting that that paper not only surveyed exclusively parents but also recruited exclusively from transphobic websites (small wonder the parents found weren't particularly supportive). To the point where the conclusions had to be drastically rolled back and these failures in experimental design highlighted [0].

It's also the start and end of anyone replicating those results. This is very misleading and equivalent to linking the now debunked paper saying vaccines cause autism then telling readers to go look for more research.

For those in the back, trans people are the gender they say they are and the last people you should be asking for their opinion on a person's identity are their unsupportive parents. [0] https://journals.plos.org/plosone/article?id=10.1371/journal...