Little v. Hecox

In 2020, Idaho enacted the “Fairness in Women’s Sports Act,” recognizing the reality of biological sex and ensuring that women and girls are not forced to compete against men and boys who benefit from the enduring physical differences between men and women.

This was the first state law to bar transgender girls and women from female-designated teams in public schools from K–12 through college. However, following the law’s passage, a biological male, who identifies as female, sued the state, alleging a violation of the Equal Protection Clause of the Fourteenth Amendment. The district court issued a preliminary injunction, blocking enforcement of the law, and the Ninth Circuit affirmed. The state sought further review by the United States Supreme Court.

In 2024 and 2025, Do No Harm filed amicus briefs at the Supreme Court in support of the State of Idaho.

The briefs first explain (1) that sex is binary, rooted in biology, and distinct from gender identity, which is a psychological state; (2) that intersex conditions are rare disorders of sexual development and should not be conflated with transgender identity; and (3) that biology-denying interventions such as puberty blockers and cross-sex hormones are dangerous, lack compelling evidence, and carry unknown risks in addition to known physical harms.

The briefs go on to point out that the Ninth Circuit’s decision contains numerous glaring scientific and legal errors. For example, the appeals court (1) wrongly assumed that biology denying interventions are inevitably necessary and appropriate; (2) ignored or misunderstood the nature of sex as distinct from gender identity and the consequent fact that gender identity does not alter a person’s sex; and (3) mischaracterized the prevalence and relevance of intersex conditions to the dispute at issue.

On June 30, 2026, the United States Supreme Court held in favor of Idaho, reversing the Ninth Circuit and concluding that the state may maintain separate women’s and men’s sports teams defined by biological sex and did not violate the Constitution by doing so.