The Witch Boy by Molly Ostertag
In thirteen-year-old Aster's family, all the girls are raised to be witches, while boys grow up to be shapeshifters. Anyone who dares cross those lines is exiled. Unfortunately for Aster, he still hasn't shifted and he's still fascinated by witchery, no matter how forbidden it might be. When a mysterious danger threatens the other boys, Aster knows he can help — as a witch. It will take the encouragement of a new friend, the non-magical and non-conforming Charlie, to convince Aster to try practicing his skills. And it will require even more courage to save his family...and be truly himself.
Review from School Library Journal Starred:
Aster belongs to a magical family, but he is having problems with one of the most basic rules: shapeshifting is for boys, while witchcraft is for girls. Aster is fascinated by the spells that the girls are learning, so he spies on their lessons whenever he can. When several boys disappear during shapeshifting practice, Aster realizes that he can help save them using witchcraft to battle a strange and powerful enemy—but he'll have to break his family's traditions and risk his life. Both the plot and the overall message are straightforward and familiar but engaging. Beneath the fantastical elements lies a story about upending gender expectations, forging identity, and uncovering heroic potential in oneself. Those who enjoy sci-fi or fantasy stories about protagonists who must prove that their society's rules are flawed will appreciate this offering. Ostertag's bright, gentle, cartoonlike artwork brims with life and adds extra appeal to this fast-moving story.