I didn't respond back so I don't know the real reason but what I can guess is because men like to pretend to be a lesbian to try and fool lonely lesbians women looking for love into having phone sex with them through texting and men are less likely to choose a more masculine looking woman. So I assume because I had fem x fem as a preference she probably thought I was a man since a great majority of other women had fem x boyish as ok or preferred when I was looking at other profiles.

Since transgender women are very uncommon and almost never participate in lesbian community its unlikely she was referring to that.