These days, it is practically impossible not to hear about some aspect of transgender life. Whether it is the bathroom issue in North Carolina, trans people in the military, or on television, trans life has become front and center after years of marginalization.

And kids are coming out as trans at younger and younger ages, which is a good thing for them.

But what written resources are available to parents, teachers, and mental health professionals who need to support these children?

Elijah C. Nealy, a therapist and former deputy executive director of New York City's LGBT...