Federal Government Mandates Biological Sex Definitions for All Laws: Gender Identity Excluded from Recognition

The “Defining Male and Female Act of 2025” is a short bill with a massive scope: it mandates that every federal law, rule, and interpretation must adhere to a single, strict, biological definition of sex. Essentially, it’s locking down how the entire federal government talks about who is male and who is female, and it’s doing so with language that leaves no room for anything else.

The New Federal Dictionary: Biology at Conception

This bill inserts new, fixed definitions into Chapter 1 of title 1 of the U.S. Code, which acts as the bedrock for interpreting all other federal legislation. The core change is the definition of Sex, which is now defined as an “unchangeable biological classification as either male or female, determined by biology as defined right here.” Translation: it’s an immutable classification, set in stone.

It then defines Male as a person belonging to the biological sex that produces sperm at conception, and Female as the sex that produces eggs (ova) at conception. This ties identity strictly to reproductive biology determined at the earliest possible stage. For federal agencies, this means that every document, every form, and every regulation must now operate under these specific biological constraints.

What Happens to Gender Identity?

Crucially, the bill doesn't ignore gender identity; it explicitly addresses it to remove its legal standing. The bill states that Gender Identity is an “internal, subjective sense of self” that is “separate from biological reality and sex.” Because this identity “doesn’t offer a meaningful basis for identification under federal law,” the Federal Government will no longer recognize it as a replacement for biological sex.

This is the provision that will cause the most friction. If you’re a transgender person, this means that for the purposes of federal law—think of things like federal housing protections, healthcare programs, or even how your identity is recorded in federal databases—your gender identity is legally irrelevant. Any existing federal rule or interpretation that currently allows for recognition based on gender identity would likely be overridden by this new, mandatory definition.

Redefining Family and Age

The bill also uses these new biological definitions to clarify common terms. A Mother is defined as a female parent, and a Father is a male parent. Man is an adult male, and Woman is an adult female. While this might seem like just common sense language, in the context of federal law, it matters. For instance, if a federal program offers specific benefits or protections to 'mothers' or 'fathers' (like certain parental leave or social security benefits), those terms are now strictly tied to the biological sex assigned at conception. This removes any ambiguity, but also removes the flexibility agencies might have used to include all parents regardless of their gender identity.

The Real-World Impact on Federal Programs

Because this bill applies across all federal laws and rules, its impact is sweeping and immediate. If you rely on any program administered by a federal agency—from the Department of Education to the Department of Housing and Urban Development—that program must now ignore gender identity and adhere only to the biological definition of sex.

For example, if the Department of Education has rules about bathroom access or sports participation that currently allow students to participate based on their gender identity, those rules would have to be scrapped or rewritten to align with the “immutable classification” based on reproductive biology at conception. This isn't just about forms; it’s about access, protections, and recognition under the law for millions of people. It essentially forces every federal agency to use a single, narrow lens when viewing sex, regardless of the program's specific needs or the population it serves.