You do realize that there's no such thing as AN XY chromosome or AN XX chromosome, right? There's an X chromosome, and a Y chromosome, and they can be thrown into almost any configuration. Also, XY women (e.g., people with AIS) wouldn't fit into this definition, nor would XXY, XYY, XXYY men, or XO, XXX, or XXXX women, to name a few. And then there are the wonderful conditions that result in mosaicism.

Moreover, I'd venture to say that most trans* people have never had genetic testing and wouldn't know their own karyotypes anyway.