Is it transphobic to refer to trans people as a "third sex". I was wrongly using the word "tranny" to refer to trans people mainly due to ignorance about the word triggering people but I still got flak when I refering to trans people as a "third sex" (as in along the lines of the Japanese term "new half").

I don't consider trans people any different than other people but as a cis heterosexual male I could never date someone who used to be male just because of personal bias.

What's people's opinions on the whole matter? Am I in the wrong?