Authors Say Agents Try to “Straighten” Gay Characters in YA -- includes an account of an agent telling authors to make straight or entirely remove a viewpoint character who is gay. Note that this is an agent, not a publisher. There's a list of What You Can Do, for publishers, agents, writers, readers and reviewers. I would like to see more gay and/or non-white and/or other "minority" leads and major characters in all types of fantasy and science fiction, and fiction in general.
I am a white person who grew up in a predominantly white community, reading sci-fi and fantasy, and romances, and mysteries, and none of the things I read except comic books (which have their own problems) really reflected a diverse world.
(I think Claudia in the babysitters club was meant to be Japanese? But it wasn't really dealt with, that I recall -- I'm pretty sure I remember reading at least one book where she didn't know how to use chopsticks, for example; her cultural heritage was not present.)
Interesting update! So, a company of literary agent-type stuff (I'm not sure what to call them -- help, anyone?) read the above article and reacted like most of us, i.e. "I can't believe someone did that to them! That's terrible, and they are absolutely right about the need for more diversity in YA fiction."
And then they found out the authors meant were talking about them.
Here is their response. To summarise: Rachel Manija Brown and Sherwood Smith are misrepresenting the conversations that happened betweeen them and this agent (the company gives their side of the story), which is exploitive of the issue (and the agent!) -- however, the issue of greater diversity and more glbt characters in YA fiction is important and we should discuss it and do stuff about it (so long as our discussion is based on honesty).