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 ...

Biological sex is the sole basis for defining the words “male,” “female,” “father,” and “mother,” according to new guidance published Wednesday afternoon by the Department of Health and Human Services ...

Introduction: Carving nature at its joints, or Why birds are not dinosaurs and men are not apes -- Part I. The Interrelationships of Organisms: 1. What this book is about -- 2. Classification -- Part ...