In medieval times, maps warned adventurers away from unexplored territories with drawings of mythological beasts and a warning that read, “Here be dragons.” Are we venturing into dragon territory with the transitional therapies increasingly made available to transgender youth? 12-16-18 Twelve-sixteen-eighteen isn’t a date, it’s a program developed in Holland for treating children experiencing gender dysphoria, the condition of feeling there is a mismatch between one’s experienced gender and one’s biological sex. When Dr Norman Spack, pediatric endocrinologist at Boston Children’s Hospital, learned of the approach, he decided, “I’m going to do this.” And he did. In 2007, Dr Spack co-founded the hospital’s Gender Management Service (GeMS), the first clinic in North America devoted to treating transgender children. There, he implemented the 12-16-18 program, which has since been adopted by clinics nationwide. (Dr. Spack did not respond to an interview request.) Hormones are the tools of the endocrinologist’s trade, which is why, in 1985, a transgender Harvard graduate sought Dr. Spack’s assistance. The patient, born female, had lived as a male named “Mark” throughout his …