I am one of the gay men that is not interested in women sexually. I've done 3ways with married couples, but my interest was always in the other guy. But when if comes to just me and a woman (cis or trans), I've lost all interest.
There are 2 instances where I tried to have sex with a guy who was dressed in women's clothing and I couldn't do it. The first guy used to come into the adult bookstore that I worked at. He was a very good looking guy, nice body. He would get quarters and go into a booth with a gloryhole. He would put all of the quarters into the machine and then he would put lipstick on his face, take his shirt and pants off to reveal that he was wearing women's panties and a bra. He would sit there and jack off. If somebody came into the other booth, he would mess around with them through the gloryhole. When he presented as a man, I thought he was very hot. The first time I saw him through the gloryhole, he just had his dick out and it was very nice. But when he dropped his pants and showed what he was wearing underneath, I lost interest. My mind was hardwired that I now saw him as a woman.
The other time was a guy that used to come to the gloryhole at my house. He was my age and usually showed up wearing just sandals, baggy shorts and a t-shirt. He came over many times, I would suck his dick, he might fuck me, and he would leave. One night, he invited me over to his house. I was horny, so I got the address and told him I would be there in 30 minutes. When I pulled up to this house, he was sitting outside but it was very dark and I couldn't see him very well. When we walked into his house, I saw that he had on a wig, makeup and women's clothing. My dick had been hard on the trip to his house, but when I saw him, it immediately went soft. He tried to suck my dick to make it hard, but I never did get hard after that. I sucked his dick for a little bit, but I finally told him this wasn't working for me and I left. I felt bad, but I just couldn't do it.
The first guy was about 15 years ago. The second guy was maybe 5 years ago. Both of them were good looking guys, but when I saw them in women's clothing, my mind saw them as women and I had no interest. In the last few years, I have watched some porn videos of FTM guys having sex. They present as men, they've had breast reduction surgery but they still have a vagina. I find them pretty hot. Something about them really turns me on, and I have jacked off to many of their videos. I think their masculinity is what I find hot. I haven't tried to have sex with a FTM yet, but I wouldn't rule it out.