Levithan says he wrote Boy Meets Boy because it was the kind of book he wished would cross his desk as an editor: "a book about gay teens that doesn’t conform to the old norms about gay teens in literature (i.e. it has to be about a gay uncle, or a teen who gets beaten up for being gay, or about outcasts who come out and find they’re still outcasts, albeit outcasts with their outcastedness in common)." He seemed to have his desired effect, because one reviewer described it as "the first upbeat gay novel for teens."
My class was discussing the importance of books like this for young adults: Two Boys Kissing uses the kiss as its crystallizing event, but as there's not much a pair of kissing people can actually do, most of the book focuses on other gay boys, in a wide variety of situations and from a wide variety of backgrounds, each of whom is affected by the kiss in some small way. I would argue its project is to "normalize" same-sex male relationships by depicting them as normal, and thus by depicting a lot of them, so that none of them is the gay relationship. They're as diverse as any relationship is.
Which got me thinking. Boy Meets Boy came out in 2003, the same year I graduated high school, so I certainly didn't read it as a teen myself. But did I read any young adult novels featuring queer characters? I've been wracking my brain for two days now, and I can't think of any.
As far as I can remember, in fact, the first work of fiction I read with a non-heterosexual character in it was in fact a Star Trek novel, a spin-off novel called The Best and the Brightest about a group of cadets at Starfleet Academy. Two of them are women, and they end up in a relationship. I remember rereading bits of the novel, certain that I had missed or misunderstood something, and that one of them was a man. But no. The book came out in February 1998, so if I read it around the time it came out, I would have been in seventh or maybe eighth grade. The book presents it as completely normal: like no one even comments on the same-sex thing, though I feel like there was some uncertainty because one of them is an alien. (The Best and the Brightest was the first unambiguous depiction of a same-sex relationship in Star Trek. I found a nice 1998 article about here when researching this piece. The novels have had many more since; televised Trek has been less progressive, though maybe there's hope with Star Trek: Discovery.)
Compare that to the year 2017, where non-hetero characters appear in family television programs like Doctor Who, and Sulu turned out to be gay married in last year's Star Trek film. It's a different and still-changing world we live in.