Boy Meets T-Girl

A subtrope and variant of one of the most basic and oldest plots, which originally went: Boy Meets Girl, boy loses girl, boy finds girl again. But with a twist.

One of the pair is the inevitably shy and innocent boy next door - a straight stock character. The other is inexplicably gorgeous, intelligent, sympathetic, single and seemingly perfect in every way... but for one minor detail, which serves as a source of dramatic tension at her expense for most of the story. She was assigned male at birth; her backstory involves a long and difficult transition, of which the boy who's just been smitten by her has no inkling or idea. Effectively, she's left wondering how he will react once he learns of her past - and he will be caught completely off-guard, to the point that that he risks losing the girl if he reacts the wrong way or (if she's "outed" by someone else) fails to defend her honour.

The Reveal is usually played in one of two ways. If this is being written as porn or erotica, she's transformed into a futanari-like fetish object that acts as "the best of both worlds" sexually, with all the Unfortunate Implications that can carry. If this is being written as the sort of teen fiction which turns up in public libraries, she becomes An Aesop - a lesson to bullying teens not to judge others on the basis of their sexuality.

Another variant involves a fellow falling for a transgender woman in some context where he knows (or at least suspects) what's going on, but where his family, friends or colleagues don't know (and react negatively or even violently when they learn the truth).

Despite the trope title, Boy Meets T-Girl could just as easily be played the other way around; there are just as many transsexual persons transitioning female-to-male as male-to-female. As indicated, the straight boy/trans woman pairing is more common because a transgender woman is a more readily sexualised character (see Attractive Bent Gender and Everybody Wants the Hermaphrodite), but at the same time, more free to express emotion if the main character allows anyone to hurt her in some way - as Men Don't Cry, but trans women (as they are women) do. And yes, real life is more complicated as there are various possibilities to match trans people with other LGBT community members who would be more aware of the issues and the discrimination involved.

Not to be confused with Something's Different About You Now, where the lad already knew the lady before transition.

See Transsexualism and Transgender. See also the older-than-dirt parent trope, Boy Meets Girl.

Anime and Manga

 * Family Compo plays ping-pong with the trope, as a guy winds up living with a transgender family and is attracted to the "daughter" of the family, who tends to switch between being a "boy" and a "girl" as often as they change clothes, and the story tends to leave what they really are under said clothing up in the air.

Film

 * The Crying Game has a man unwittingly fall in love with a transwoman as just one more twist in an already-complex plot.
 * Soldier's Girl has a soldier fall in love with a transgender showgirl. He's fine with her status, two of his fellow soldiers are not.
 * Transfixed (2015) is an Alon Kol documentary about a pair of Asperger Syndrome patients (Martine Stonehouse and John Gelmon) in a highly unconventional romance. Despite their social limitations (an autism spectrum disorder that makes communication with others extremely difficult), both dream of getting married but straight-identifying John presumably won't tie the knot until Martine is able to complete her sexual reassignment surgery.
 * XXY (2007 film) has a boy fall in love with an intersexual main character, who is living as a teen girl but hiding that she medically has some characteristics of both genders (as XX is the usual genetic code for a lady and XY for a gentleman, XXY is unusual and rare).

Literature

 * Almost Perfect by Brian Katcher. Written by a schoolteacher whose own daughter is the age of the trans girl in the story, it's basically an Aesop aimed at a teen-fiction audience.
 * If I was your girl, by Meredith Russo. This is more of the same, but tends to stretch a bit further to try to get a happy ending as the author is a transgender woman.

Live-Action TV

 * Transparent (Amazon video series): Josh (Jay Duplass) and his crush on Shea (Trace Lysette) in season three.