The reason why gay marriage will pass before transgender rights is that the gender construct is not challenged. When the binary construct is challlenged it makes people think what masculinity and femininty really is.
The stuff society is handled down on what it is to be feminine or masculine is to me short sighted and limiting. Not everybody is going to fit into that box. IMHO, many transgender people have committed suicide or suffer from depression because people will not accept them for who they really are. I'm 60 years old and I have yet to meet a male whose manly masculine or femme feminine.
Gennee