The History of Gender Definition in the U.S. and the Federal Policies Behind Decades of Controversy

In the United States, the history of gender definition in the U.S. reflects not only cultural change but also deep shifts in federal gender policies, legal rulings, and government-led social programs. For decades, the government’s definition of gender has been shaped by gender identity laws in U.S. history, civil rights movements, public opinion, and judicial interpretation. From binary-only classifications to the brief legal recognition of nonbinary options, these changes in American gender definitions highlight a persistent debate at the intersection of law and identity.

This article provides a comprehensive, fact-based overview of how federal and state governments have approached gender identity from early legal standards to the rise of modern gender identity in public policy. We examine key legislation, court decisions, and administrative actions to understand how the legal definition of gender continues to evolve and how its implications extend across healthcare, education, the military, and more.

Recognized Gender Identities in the U.S.: A Growing List

Historically, U.S. federal policy recognized only two genders—male and female—based on biological sex at birth. However, over the past few decades, advocacy, academic research, and social change have expanded the conversation around gender identity.

While the legal recognition of gender identities varies across states and federal programs, here is a list of gender identities commonly acknowledged in medical, academic, and sociocultural contexts:

• Male – Traditionally assigned at birth based on biological characteristics.
• Female – Traditionally assigned at birth based on biological characteristics.
• Transgender – A person whose gender identity differs from the sex assigned at birth.
• Nonbinary – A broad category for gender identities that are not exclusively male or female.
• Genderqueer – Similar to nonbinary; often used to challenge traditional gender norms.
• Genderfluid – A person whose gender identity may change over time or depending on the context.
• Agender – A person who identifies as having no gender.
• Bigender – A person who identifies with two genders, either simultaneously or alternately.
• Two-Spirit – A culturally specific identity among some Indigenous North American tribes that may encompass gender, spiritual, and social roles.
• Demiboy / Demigirl – Partially identifying as male or female, but not fully.
• Intersex – A biological variation; individuals born with physical sex characteristics that don’t fit typical definitions of male or female. While not a gender identity, it intersects with gender policy.

During 2022, at least 21 U.S. states allowed individuals to select an “X” marker for gender on identity documents such as driver’s licenses. In 2021, the U.S. State Department began allowing “X” on passports as well although this policy was rolled back in 2025 under a new executive order.

It’s important to note that legal recognition does not always equate to protection. While some federal and state laws offer protections based on gender identity, others restrict recognition to the binary categories of male and female. This has created inconsistencies in how individuals are classified, protected, and served by government institutions.

Common Gender Identities and Their Legal Recognition in the U.S.

Note: As of 2025, the U.S. federal government reverted to a binary definition of sex (male/female) through executive order. However, several states continue to allow “X” gender markers and recognize nonbinary and transgender identities in legal documents and anti-discrimination laws.

Early Federal Gender Definitions (Pre-20th Century to 1950s)

Throughout early U.S. history, gender was equated strictly with biological sex, typically marked male or female on official records. Policies around voting rights, military service, and public roles followed a binary framework, codified by state and federal laws. No legal recognition existed for gender identities that diverged from assigned sex at birth. Marriage, labor protections, and suffrage laws were all crafted around this binary.

Civil Rights Movements and Shifts in Language (1960s–1980s)

The rise of the civil rights and women’s liberation movements led to legal reforms such as Title VII and Title IX, which addressed sex discrimination in education and employment. However, these laws used the term “sex” rather than “gender,” leading to decades of debate and litigation over interpretation.

As noted by NCBI, a growing divide between biological “sex” and socially constructed “gender” began appearing in public policy and academia—marking the early emergence of gender identity in public policy.

From Policy Silence to Recognition (1990s–2010s)

During the late 20th and early 21st centuries, definitions of gender in public policy expanded. Federal agencies began to acknowledge gender identity as distinct from biological sex. Executive orders and guidance documents extended protections under Title IX and Title VII to transgender individuals, although inconsistently across administrations.

The U.S. Government Accountability Office (GAO) reports that federal gender-related policy began incorporating more inclusive language and data collection standards during this time, although not uniformly. In education and healthcare, gender identity became increasingly recognized in program implementation.

Policy Backlash and Reversal (2016–2020)

The federal stance on gender became more restrictive during this period. Efforts to define gender solely by “immutable biological characteristics” at birth surfaced in official memoranda and proposed rules. In 2018, the Department of Health and Human Services drafted guidance to interpret “sex” as binary across federal programs. These proposals faced legal challenges and were not always finalized, but they highlighted the controversies surrounding gender policy.

The Equal Rights Amendment and Equality Act have been key legislative battlegrounds. While both aim to protect individuals from discrimination based on sex and gender identity, their passage and enforcement remain politically divisive.

Renewed Efforts Toward Binary Definitions (2021–2025)

Recent federal directives have re-emphasized the recognition of only two sexes in government policy. Executive orders in 2025 redefined “sex” in federal law to mean male or female, determined at birth. These policies reversed prior rules that permitted nonbinary gender markers on identification documents like passports.

In military contexts, the Brookings Institution has chronicled ongoing debates over gender roles, especially in combat assignments. These discussions underscore how gender classification affects eligibility for service, benefits, and legal protections.

Public Policy Implications and Federalism

The shift back to a binary model of gender has major implications for civil rights enforcement, healthcare access, education protections, and military service eligibility. Meanwhile, many states have enacted their own laws expanding or restricting gender recognition, creating a patchwork of standards across the U.S.

As outlined in a Western Kentucky University thesis, the disconnect between federal and state gender policies often leads to legal uncertainty, especially in cases involving education rights, parental identification, and anti-discrimination statutes.

The Role of the Courts in Gender Definition

Federal courts have played a critical role in shaping how gender is interpreted in U.S. law. Since statutory language often uses the word “sex,” courts have repeatedly been called upon to determine whether this term includes gender identity.

One of the most pivotal rulings came in 2020 with Bostock v. Clayton County, where the U.S. Supreme Court held that discrimination on the basis of gender identity or sexual orientation constitutes sex discrimination under Title VII of the Civil Rights Act of 1964. Although the ruling addressed employment law, it set a legal precedent that has influenced other areas of federal interpretation.

The GAO highlights how judicial decisions have been essential in resolving ambiguities around federal policy language, particularly in contexts where no formal legislation existed to guide agency enforcement.

Public Opinion and Cultural Shifts in Federal Gender Policy

Over time, shifts in public perception of gender identity have influenced the direction of federal policy. In the late 20th century, public discourse around gender was largely binary, but by the 2010s, increased visibility of transgender and nonbinary individuals pushed these conversations into mainstream culture and politics.

As shown in the WKU thesis, the cultural divide over gender identity has created a political flashpoint in policymaking, where federal definitions may change drastically with each administration.

Public opinion polling shows generational differences in support for gender-inclusive policies, with younger Americans generally more supportive of legal recognition beyond male and female classifications. These cultural shifts helped shape executive guidance, especially during the Obama administration, but also triggered backlash that continues to shape federal gender policies today.

Policy Impacts Across Sectors

The legal definition of gender affects more than identity documents—it has widespread implications across sectors:

• Healthcare: Gender classification influences access to procedures, provider coverage, and protections under anti-discrimination rules.
• Education: Title IX interpretations determine how schools handle sports participation, bathroom access, and name/gender changes.
• Military: Eligibility for service and assignment varies with gender classification.
• Workplace: Gender identity protections impact hiring practices, dress codes, and harassment policies.

Changes in federal definitions ripple into these sectors, influencing both policy implementation and litigation risk.

The history of gender definition in the U.S. reveals a long and evolving policy journey from rigid binary roles to broader recognition and, recently, back toward biological determinism in federal law. Through laws, court rulings, and administrative directives, gender remains not just a matter of personal identity, but a central theme in national policy debates.

Understanding how federal definitions have changed, and continue to change, offers essential insight into the intersection of law, identity, and government in American life.

References:

NCBI. Understanding the Difference Between Sex and Gender

U.S. Government Accountability Office (GAO). Women and Gender in Public Policy

Columbia Law School. The Equal Rights Amendment and the Equality Act: Two Equality Measures Explained

Brookings Institution. Women Warriors: The Ongoing Story of Integrating and Diversifying the Armed Forces

Western Kentucky University. Gender and Federal Policy: A Historical Review of Legal Recognition in the U.S.