A great deal of women I have been initially attracted to were transsexuals. But when I got to know them better, I was unable to identify them as female anymore, hence they just 'died' emotionally.
The surrounding considerations are extremely warranted.
So, your instinct says "attraction" and then your mind takes over?
No, attraction itself is not instinctual, and what is 'mind' supposed to be in context even. I don't even know how you can misinterpret what I wrote so wrong in the first place.
Attraction depends on certain features that are considered desirable, in respect to your sexual orientation. That can be if you have a shared interest or if someone has certain personality features, the way they behave, etc or just very bluntly if they smell good or look pretty (which is not very likely to be important over the internet). I find a large skull size very attractive, unfortunately that is also a rather male feature, like other aspects, for example being interested in programming or being obsessive, rational, aggressive, dominant, etc. There are real women who are like that, but it is so rare that they are likely outnumbered by transsexuals.
When you do not know someone in depth, you have to assume a lot of detailed information about them which you have no solid confirmation of by experience. That is how someone transsexual can initially be rather like a woman (or simply ambiguous, so that you can rationally decide what is true) to your perception, only to be 'corrected' into a male by your sense of reality and emotional perception later, if it is fed with the actual details you couldn't be aware of before.
"Is she gone yet?"