This open access book originates from the 36th Ernst Strüngmann Forum, where in 2023 scholars from a wide range of disciplines came together to advance understanding of gender, sex, and their entanglement. Although these interdisciplinary discussions revealed no single approach to the conceptualization or operationalization of sex/gender entanglement, they did uncover a high degree of convergence. Driving this project was the pressing need for constructive, interdisciplinary dialogue, as clearly articulated arguments grounded in rigorous, principled scholarship are required to promote sound application in research, policy, medicine, and public health.At the Forum, open debate is a given, but science does not operate in isolation from the political and social forces around it. This became starkly evident in 2025, when newly instituted policy interventions and measures impacted research and knowledge production in many areas of science, interfering not only with the first edition of this volume but, more broadly, affecting the lives of many individuals.The second edition seeks to redirect attention back to sound science. Together with updates throughout and a restored chapter on brain transcriptomics, this edition advances rigorous, interdisciplinary scholarship on sex/gender entanglement and illuminates viable paths forward.