When the U.S. Supreme Court heard oral arguments in Little v. Hecox and West Virginia v. B.P.J., the justices were not inventing new questions. They were wrestling with the same unresolved issues that lawmakers, parents, and athletes—particularly in North Carolina—have been debating for years.

At the heart of the cases are state laws in Idaho and West Virginia that bar transgender women and girls from competing on female sports teams. Critics frame those laws as discriminatory. Supporters argue they protect fairness in women’s sports. What became clear during oral arguments is that the Court was confronting a deeper problem that long predated these cases: what “sex” means in law, and who has the authority to define it.

That question has sat at the center of the Title IX debate for years, and it is one I warned lawmakers about long before it reached the nation’s highest court.

In a 2021 opinion, “Shifting interpretation of Title IX demands action from lawmakers,” I argued that Title IX was enacted to prevent discrimination based on biological sex, not an evolving concept of gender identity. I cautioned that allowing federal agencies and courts to redefine “sex” without legislative action would inevitably lead to confusion, conflict, and litigation.

Congress has now acted to clarify the meaning of sex in the context of Title IX athletics under the Protection of Women and Girls in Sports Act. But the fact that this issue reached the Supreme Court before that clarification underscores the cost of legislative delay—and helps explain why the Court’s questioning mirrored concerns that had been raised years earlier.

During oral arguments, Justice Ketanji Brown Jackson framed the dispute as one of definition, noting that the law would recognize as “girls” only those “assigned female at birth.” What was once a category grounded in biological reality had, for years, been treated as a matter of linguistic convention, leaving courts to debate terminology rather than the physical differences that originally justified sex-based sports. That was precisely the problem I flagged when lawmakers first began deferring the issue.

Justice Samuel Alito pressed the same point from another angle, asking how a court can evaluate claims of sex discrimination without first knowing what “sex” means for equal-protection purposes. His questioning illustrated the institutional dilemma courts face when foundational terms are left undefined and judges are asked to supply meaning on their own.

This tension—between sex as a biological reality and gender as a social expression—was central to my earlier analysis and became a focal point of the Court’s questioning.

In a second 2021 article, “More than ‘inclusion’ must be considered for trans participation in girls sports,” I anticipated another theme that featured prominently in the arguments: fairness. While inclusion is an important social value, I argued that it cannot be the sole principle governing competitive athletics. Sex-based sports exist because physical differences between males and females—particularly those that emerge around puberty—affect strength, speed, and endurance in ways that matter for competition. That concern surfaced repeatedly during oral arguments, as justices questioned whether inclusion alone can justify policies that may disadvantage female athletes. The skepticism reflected a broader recognition that redefining fairness to mean inclusion at all costs risks eroding the rationale for women’s sports and the protections Title IX was designed to provide.

In a third article from that year, “Desperation grows for those opposed to bill barring biological males from female sports,” I predicted the political dynamic that has since played out nationally. I argued that opposition to sex-based sports protections increasingly relied on emotional appeals and institutional pressure rather than clear statutory interpretation or scientific grounding. During oral arguments, the justices showed little interest in slogans or abstractions, returning instead to first principles: statutory text, equal-protection doctrine, and the limits of judicial power.

By the end of the hearings, many court watchers concluded that a majority of justices appeared inclined to defer to legislatures rather than rewrite Title IX from the bench. That posture does not represent a sudden shift. It reflects a recognition that courts are ill-suited to resolve cultural disputes that arise when lawmakers fail to clearly define the law they enact.

The Supreme Court did not stumble into this debate. It arrived there because lawmakers—at both the state and federal levels—delayed answering a basic question: are sex-based protections grounded in biology, gender identity, or some combination of the two?

Congress has now answered that question for women’s sports under Title IX. But the path to that answer illustrates a broader lesson. When legislators avoid defining foundational terms, courts are left to referee disputes they were never meant to resolve. The Court’s engagement with these cases makes clear that it is no longer willing to pretend those questions do not exist—and that legislative clarity, when it comes, matters.