Many good books have been suggested already. I would add:
1. The Absolutely True Diary of a Part-Time Indian by Sherman Alexie where a young Native American boy is the only Indian in the entire school besides the school mascot. I was interested because I have relatives facing modern Native American issues revolving around racial attitudes in this country.
2.The Girl Who Fell From the Sky by Heidi W. Durrow where a young girl is forced to live in the United States and face racial attitudes toward mixed-race children. I just finished reading this and had to contrast the racial attitudes of the U.S. versus Denmark, or in my own case, in several countries in South America.
3. Graceling by Kristin Cashores is a fantasy book about a girl who is born with eyes which don't match which in her country is supposed to give her magical powers. This book would depend on whether you enjoy fantasy books or not.
4. Make Lemonade by Virginia Euwar Wolff which deals with the effects of teen pregnancy in realistic terms without preaching.
5. A Wild Ride Up the Cupboards by Ann Bauer, House Rules by Jodi Picoult, and the curious incident of the dog in the night-time by Mark Haddon all which deal with autism in both serious and funny ways. These books deal not only with the person with the diagnosis, but the incredible effects on the families. Having been one of those families, the books portray true emotions.
6. If you like non-fiction, I would recommend a heavier read--The Immortal Life of Henrietta Lacks by Rebecca Skloot which is about a black woman whose cells were used without her consent to make important medical discoveries and millions of dollars for the researchers who used her cells while she was given no say and no money. The injustice is stunning.