Hands down, the first book everyone should have is a basic anatomy book. It has been the main go to and lead up, cause after all, the girl parts are just one aspect to their whole body health, and we can talk about it long before the dreaded first period. But more than that, it gives us a practice tool to talk about caring for our body, in times of health and in injury. When your kid gets an ear infection, show them the ear section. When they get a cut or scrape, or stiches, show them the skin section.
