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Updated: Jul 27, 2026

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making
Published on: March 2, 2011
Impossible "Choices": The Inherent Harms of Regulating Women's Testosterone in Sport
Katrina Karkazis1, Morgan Carpenter2,3,4
1Global Health Justice Partnership, Yale University, 127 Wall Street, New Haven, CT, 06511, USA. katrina.karkazis@yale.edu.
Abstract:
In April 2018, the International Association of Athletics Federations (IAAF) released new regulations placing a ceiling on women athletes' natural testosterone levels to "ensure fair and meaningful competition." The regulations revise previous ones with the same intent. They require women with higher natural levels of testosterone and androgen sensitivity who compete in a set of "restricted" events to lower their testosterone levels to below a designated threshold. If they do not lower their testosterone, women may compete in the male category, in an intersex category, at the national level, or in unrestricted events. Women may also challenge the regulation, whether or not they have lowered their testosterone, or quit sport. Irrespective of IAAF's stated aims, the options forced by the new regulations are impossible choices. They violate dignity, threaten privacy, and mete out both suspicion and judgement on the sex and gender identity of the athletes regulated.
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