Unsettling Gender Reveal/Playing With

Basic Trope: A "female" character turns out to be a male instead, squicking out someone who was romantically attracted to him/her.
 * Straight: Alice and Bob meet. Bob falls for Alice. Then Alice turnes out to be "Andy". Bob is upset.
 * Exaggerated: Alice and Bob meet. Alice has Gag Boobs and a Stripperiffic outfit, but is still a guy. Hilarity Ensues.
 * Justified: Alice is a Wholesome Crossdresser, a shapeshifter, a transsexual, or is the victim of a Gender Bender.
 * Or, Alice had undergone plastic surgery.
 * Inverted:
 * Samus Is a Girl: Bob meets Alice thinking that "Alice" is a man, only to be distraught when she's revealed to be the real deal.
 * Sweet on Polly Oliver.
 * Subverted: Bob thinks Alice is secretly a guy, gets upset, but Alice is the genuine article...
 * Alternatively: Bob is shocked and flustered... But it turns out he's bisexual (or is only gay for Andy) and is just upset that Andy didn't trust him enough to tell him the truth.
 * Also alternatively: Alice used to be a man, but Bob still loves him anyway.
 * Double Subverted: Bob thinks Alice is a guy, gets upset, but Alice isn't actually a guy... Unfortunately, Bob's spent all this time talking to Alice's Half Identical Twin.
 * Also: Alice used to be a man, but Bob still loves her. That is, until Bob realizes that Alice said "I used to be a man", not "I'm from Iran."
 * Parodied: Alice and Bob meet. Alice is blatantly a man dressed as a woman, but Bob falls head over heels for "her" anyway. Later he is shocked to find out "she" is is a man.
 * Deconstructed: Bob can't handle the truth and goes insane, kills himself, or kills Andy. Andy is the victim of intense persecution for his habits.
 * Reconstructed: Bob doesn't mind the fact that Andy is really a guy.
 * Zig Zagged: Alice and Bob meet and fall in love. Alice turns out to be "Andy". Then Bob turns out to be "Betty".
 * Averted: Everyone is the gender they appear to be.
 * Alternatively: Upon finding out that Alice is actually a guy, Bob is surprised but not disturbed.
 * Alternatively: His outward appearance notwithstanding, Alice is quite open about being a man, and tells Bob this when they first meet.
 * Enforced: A work that explores gender identity issues will inevitably feature a situation where someone misidentifies a person's gender, and hilarity (or tragedy) ensues.
 * Lampshaded: "Of course, the person I finally fall in love with turns out to be a guy."
 * Invoked: Andy intentionally dresses up as "Alice" in order to trick Bob.
 * Defied: Bob "checks" every female he meets very thoroughly to ensure he's not trapped in this way.
 * Discussed: "This chick I'm going out with right now is pretty cool. She knows sports, likes watching Baywatch... uh, Jeff is a girl's name, right?"
 * Conversed: "I don't know if I'm going to bother watching tonight's episode, TV Guide says Bob finds out his girlfriend Alice was born male and we all know his reaction is going to be so insensitive and horrified that it'll make pretty much every transgendered or trans-friendly viewer cringe."
 * "Don't forget us viewers who hate a certain trope..."
 * Played For Laughs: "Alice" and Bob walk into a room together, the implications are clear, but seconds later we hear Bob scream "OH MY GOD! DUDE! YOU'RE A DUDE!" and see him run screaming right through the door trying to get away from the newly-revealed Andy.