(education hat on)
It turns out that trans people often (*) have a profound and permanent sense of being male or female from their earliest memories. Since the organs we are interacting with on the forum are the gray wrinkly ones up top, that's the practically important setting.
(Not just trans people, there was that horrible case of the boy who was consistently raised as a girl after a circumcision accident. He just *knew* he was a boy regardless of the evidence downstairs and how everyone treated him).
The moderators have spent a lot of time educating themselves on the issue and ordering professional papers from the library that aren't online. Scientifically, it looks like the trans people have been right about themselves all along.
I know what you mean by "born male". Saying "male assigned at birth" is not SJW PC tyranny, it's simply more precise thinking. It's a bonus that saying it that way avoids hurting forum members.
GLAAD has some educational resources about transgender people, shorter and better organized than the trans* thread here.
http://www.glaad.org/transgender . I can't vouch for the quality. From trans* people themselves, there's a discussion near the end of "Trans* issues arising from the comic" about whether there's a non-painful way to discuss whether they're physically compatible. There isn't.
(/education)
(moderator hat on)
There's a draft of what will likely become forum rules near the end of the trana* thread in Discuss. Bottom line, we'll enforce it.
(/moderator)
(regular user hat)
Marten has hangups but has been wonderful about treating Claire as a woman in everyday life.
[PM sent explaining things further]
(*) Their experiences vary a lot.