Emma Hilton, developmental biologist at the University of Manchester and amateur sportswoman, examines the retention of male physiological advantages in sport after testosterone suppression and the necessity of protected female categories. Drawing on her research into muscle and strength, she explains why male-bodied athletes, even after hormone therapy, retain significant performance edges rooted in developmental biology, skeletal structure and prior androgen exposure. Hilton traces her involvement to cases such as Fallon Fox in mixed martial arts, where the physical mismatch produced serious injury, and critiques the scientific shortcomings of policies that attempt to regulate advantage through arbitrary testosterone thresholds or event-specific rules. She distinguishes differences of sex development from transgender identification, arguing that both raise distinct fairness and safety questions that governing bodies have often addressed with inadequate evidence. Hilton contends that the redefinition of “woman” and “female” in law and policy undermines sex-based protections in sport, prisons and other single-sex spaces, framing the issue as a deeper challenge to the recognition of sex as a material category rather than a matter of self-identification.
