Outstanding article, again! Just one quibble, if it even is a quibble. The above is a sensible theory and I agree it's the prevailing one. However, it isn't adequate support for your statement that "transness is not a social contagion".

Indeed, the above can even be consistent with a "social contagion" model. To get there, all you have to do is ask: who cares about stigma anyway? If you're really really gender dysphoric, wouldn't it be intolerable and stigma wouldn't matter?

But now all the people who are like, "yeah, this isn't really me, but...you know...maybe I should keep it a secret, it's easier" go, "wow, maybe I can explore this after all!" And the more people who do it and talk about it, the less the stigma gets.

It is a social contagion, technically, if that happens.

The specific contagion model with late-onset but presumably inauthentic or transient dysphoria has really poor support, but people wanting something to be true so badly that they fudge things to "prove" it doesn't mean that the thing isn't true; it might just be that the person trying to use evidence to show it has inadequate honesty and patience. So even there you are restricted to saying something equivalent to "the supposed evidence in favor is rubbish, so we should keep an open mind but remember that we don't actually have any good reason to believe this".

So, anyway, I agree with you on basically all the details. Just this one section heading is stronger than you can support with evidence you've provided.