Hard Love, by Ellen Wittlinger

Wittlinger, Ellen. (1999). Hard Love. New York: Simon & Schuster. 224 pages. 

Description from Alex Sanchez's Web listing:

This very hip, very contemporary novel set in the world of homemade zines (magazines) finds 16-year-old John “Gio” Galardi, Jr., falling in love with the amazing Marisol Guzman, a self-proclaimed Puerto Rican Cuban Yankee Lesbian. The two form an unlikely friendship based on zines, alienation, and dreams of escape. John questions his own sexuality as he struggles with his unrequited love for Marisol, who has no doubts at all about who she is. Hard Love is an absorbing book about loss, love, trust, family, transformation, and, interestingly, authorship. 

Available at SF Public Library.

From the Notebooks of Melanin Sun, by Jacqueline Woodson

Woodson, Jacqueline. (1995). From the Notebooks of Melanin Sun. New York: Scholastic. 141 pages.
 
Description from Alex Sanchez's listing of LGBTQ resources:

13-year-old Melanin Sun’s comfortable, quiet life is shattered when his mother reveals she has fallen in love with a woman. Adding even greater dimension to this story is the fact that Melanin and his mother are black, while the woman his mother has fallen in love with is white. Wonderfully written, as are all of Woodson’s books. While only a few of the author’s books deal with gay or lesbian characters, almost all deal with issues of race. 

Available at the SF Public Library. Is this a middle school book?

Otomen, by Aya Kanno

Kanno, Aya. (2009). Otomen. San Francisco: VIZ Media. (Originally published in Japan in 2006).

A multi-volume manga series that may or may not give insights into gay sensibilities among Japanese youth. Here's how an Anime News Network review explains the word "Otomen":

"... 'otomen' is a Japlish pun that combines the Japanese word 'otome' (maiden), with the English word 'men.' A more efficient translation of the title of this romantic comedy ... would be something like 'She-Man.'"

The protagonist is Asuka Masamune, a teenage guy who both loves "girly" things (sewing, knitting, making stuffed animals, etc.) and is a martial arts expert. He seems to have a crush on a female student in his school, which suggests he isn't gay, but another character is a male writer of female manga who thinks Asuka is the ideal manifestation of the female spirit. All this may be inexplicable to a young American reader, which may make it a good example of the social construction of gender and homosexuality. Pete owns a copy. Also available at the SF Public Library.

Luna, by Julie Anne Peters

Peters, Julie Anne. (2004). Luna. New York: Little, Brown and Company. 248 pages.