Amid the legal theater in the U.S. over sex and gender identity—triggered by a Trump administration decree that “‘sex’ shall refer to an individual’s immutable biological classification as either male ...

This paper examines whether biological age, as distinct from chronological age, could become a new basis for discrimination.

In Focus delivers deeper coverage of the political, cultural, and ideological issues shaping America. Published daily by senior writers and experts, these in-depth pieces go beyond the headlines to ...

The Department of Health and Human Services (HHS), under the leadership of Robert F. Kennedy Jr., will define sex as an "immutable biological classification" and only recognize two sexes, male and ...

Megan Molteni reports on discoveries from the frontiers of genomic medicine, neuroscience, and reproductive tech. She joined STAT in 2021 after covering health and science at WIRED. You can reach ...

List of illustrations -- Acknowledgments -- Introduction -- 1. Why classify? -- 2. The Aristotelian framework -- 3. The Darwinian pivot -- 4. Evolutionary taxonomy and the cladistic challenge -- 5.