Gender Blender, by Blake Nelson

From School Library Journal: Tom and Emma played together when they were in fourth grade, but now that they are sixth graders, they don't get along. Both are unhappy when they are teamed up for a gender-differences project for their health class. Then, a collision on a trampoline results in a body switch. As Tom and Emma frantically try to impersonate one another, each gains insight into the other's life. Just as they decide they'll have to remain switched forever, another blow to the head switches them back. Their health teacher is impressed with their reports, and Emma and Tom make tentative steps toward friendship. Physical development and differences are the focus here.

• Ages 9-12; some mature content
• Paperback, 192 pp.