Welcome!
And to answer your question: Whatever the GB says. No scriptures needed since there aren't any to address trannys. There isn't anything to address heirmorphadites either.
They will however throw in some Mosaic Law stuff which of course isnt binding on Christians. Fundamentalist groups are similar in that respect. JWS are highly fundamental to the point they tell you what you can and can't wear at all times. Nothing is left to your conscience or discernment.
Be certain to seriously investigate them as you would any other group you may wish to join.
On a side note, I had to laugh at the whole artificial insemination / surrogacy stuff. I mean really, what's that ENTIRE Jesus thing going on with Mary about ....??!!!??? An engaged artificially inseminated surrogate mom. Lol! Then there's that whole bonk your dead brothers wife because he died without any heirs thing.