UPDATE: I think she’s not so much seeking things written for children, as works of philosophy that are relatively accessible to teenagers.
A reader is seeking suitable texts by women and members of other (and overlapping) underrepresented groups for teaching philosophy to 12-15 year olds.
I hereby ask for suggestions in comments!
Feminist Philosophers 
UW (Seattle) has a Center for Philosophy for Children, with a lots of great resources: http://depts.washington.edu/nwcenter/
Last year, for a flyout for a joint position in interdisciplinary liberal arts and an elementary education program, I used a version of one of their activities for my teaching demonstration: https://drive.google.com/file/d/0B6oYmzobonqodnFKYjdMSTZidDA/view?usp=sharing
This site lists to tons of children’s books with philosophical themes, and provides guidelines for philosophical discussion for each of them: http://www.teachingchildrenphilosophy.org/wiki/Category:Book_Modules
Oppression by Frye
Little Big Minds by Marietta McCarty.
Anne Conway’s Principles–Bennett’s version at earlymoderntexts.com is accessible, and it’s just tons of fun.
I think the anthology I edited, *Philosophers Without Gods*, contains a number of essays that would be appropriate for thoughtful tweens and teens. There are essays by me, Elizabeth Anderson, and Marica Homiak — all quite accessible, I think.
TImothy Williamson’s *Tetralogue* might be a fun read as well. In fact, I strongly recommend the dialogue form; I remember finding dialogues much easier to read than philosophy papers or books when I was a teen…
I have used Barbara Montero’s “On the Philosophy of Mind” with students that age and they found it quite accessible. I have also use Susan Blackmore’s Oxford “Consciousness: A Short Introduction” and some chapters from her “Consciousness: An Introduction.”
If she’s interested in political philosophy, “The Curious Enlightentment of Prof. Caritat” by Steven Lukes might be something.