As someone who is exclusively attracted to straight men, I can sympathize with your position. In the last 1.5 years, I've had to have "the talk" many times. Their response is always one of these four:
1) That's ok. I still want to date you, but we have to keep your trans-ness a secret.
2) Wow that's hot. I want to have sex with you and still want to date you, but we have to keep your trans-ness a secret.
3) Eh, not for me, but let's still be friends.
4) WHAT THE FFFFFF? GTFO FREAK
I went into the whole pre-op TS thing expecting to always hear 3 and 4, but 1 and 2 are also surprisingly common. Straight men being attracted to transsexuals is a very real phenomenon (note the massive TS porn genre), and is believed to be a form of auto-eroticism where a man projects part of himself onto his fantasy of a beautiful woman. Straight men simply not caring about which genitalia you have is also not unheard of, but is more contingent on them becoming quickly attracted to your personality and character. From what I've observed, most of their reservations stem from the social stigma of dating a transwoman rather than actually being opposed to dating you.
My advice (and what has worked for me in the past) is to not make the earliest stages of interaction overtly sexual. That way they aren't primarily thinking about inserting their penis into your nonexistent vagina right off the bat. Let them get to know you first, make them laugh, all that sappy romantic comedy stuff. The more they're focused on the real you, the better chance they won't want to go without you.
My "success" rate (of the relationship or beginnings of the relationship not ending right after I have to break the news) is about 40%
That being said, I've found it a lot easier to just use a mainstream dating site and put the info right in my profile. That way I know the only people who message me are ones who will be ok with it.
