Being Gay means being exclusively attracted (sexually) to males. As for where "straight" ends and "gay" begins it's the first time you olook at a guy and think "I'd like to see him naked".. and that edges you half a millimetre into the "bi-curious" section of the spectrum.

As for the TS attraction, I'm guessing that most of your experience of "hot" TS girls is from pornography. These are almost exclusively women in transition, FFS, Implants etc, and often in that industry to fund the cost of a complete transformation. Being attracted to these women actually points towards heterosexuality, it is the feminininty you are attracted to, the body shape, the smooth skin, the pretty face, the gorgeous hair etc. All it really says is that genitlia has very little to do with attraction.

There is a difference between "I want/Dont want a c**k" and "I don't care if she has a c**k or not" Nature designs most guys to be attracted to women, attraction to TS girls in an advanced state of transition is merely nature doing it's thing.

Being Gay only really exists if you subscribe to a binary view of gender. You hint at it yourself.. Take a semi-passable CD in a cute dress with heels and long silky hair, and put her next to a tomboy female, short hair, no makeup.. jeans, t-shirt etc, from the back, almost every "straight" guy in the world would pick the CD as more attractive.. and even from the front, a lot of them would still say the CD was more attractive.. many of the rest would be too embarrassed or too angry that they'd picked the CD from the back and/or so worried about what that choice might mean for their sexuality that they would initiate a testosterone fuelled denial.

If you've ever thought about possibly one day being with a man, then you would probably fit under the label of "bi-curious".. If you have only ever considered being with a "hot" TS girl, and you find even CDers who are no more passable than you completely unattractive, then I suppose you could use the label trans-curious.

The only way to KNOW if you're gay, is to sleep with a man and see if you like it. if you do, and you can then find a man who you can connect to emotionally and want a relationship with.. then you're bi. If at that point you find that you're not really attracted to women anymore, then you're gay. But the fact you like trans-girls so much suggests that you'll never go beyond bisexual regardless of how you're presenting.