Jules Gill-Peterson’s Histories of the Transgender Child shows us how trans children have been “central to the medicalization of sex and gender during the 20th century” (3). Refuting the pernicious myth that transgender children are somehow a “new phenomenon” that represents shifting cultural ideas of gender or identity politics. Rather, Gill-Peterson shows is the receipts of a much longer history, wherein transgender children were part of a living laboratory to codify medicine’s hold over stabilizing the gender binary and “truth” of biological sex. Her book develops the concept of plasticity-the malleability or potential of the body to be changed-to examine how some white children were enfolded into a system that tried to normalize gender variant children into a binary (male or female), while black trans kids were often left out/not believed to be plastic (or trans) enough by gatekeeping doctors. She reminds us that trans children are not new or part of some recent identity politics crisis. Instead, the historic experiments on the bodies of transgender children from at least the early 20th century onward demonstrate the centrality of transgender children to the codification of medical sex and gender. Or as she writes, “Trans children have been forced to pay one of the heaviest prices for the sex and gender binary, silenced as the raw material of its medical formation (4).