In a non yaoi/yuri manga.

I think it means Lesbian, Gay, Bisexuals and Transvestite.

Stumbled across this when I was reading a manga with that genre/tag setting.

Is this correct?

Thank you.

High above the tree tops.

Almost right.
T is Transgender.

"lesbian, gay, bisexual, and transgender"

Yeah, and http://www.mangaupdates.com/showtopic.php?tid=23419

Hrodulf and Bjornolfr, you will not be forgotten.
[img]http://i411.photobucket.com/albums/pp199/SyberAngelGabrielle/couplesig.jpg[/img]
[color=black]And if the world were black and white,
you would be my rainbow in shades of grey.[/color]

Click 'n Play!

If I had a fantasy self, it'd be a tentacle monster.