The U.S. government’s new definition of sex

There will be a few posts on the definition of sex today, as everything “dropped”—as the kids say—at the same time.

First, on January 20, the Trump administration issued an executive order, “Defending women from gender ideology extremism and restoring biological truth to the federal government”—an attempt to efface gender ideology from the government and ensure that people’s biological sex appeared on government documents like passports. It defined “sex”, “male”, “female”, “men”, “women”, “boys” and “girls” in standard ways that were also to be used, per the specifications, in all government documents.  Gender ideology was to be eliminated from government-funded projects like grants, sex was characterized as “binary,” and the order specified things like this:

Agencies shall effectuate this policy by taking appropriate action to ensure that intimate spaces designated for women, girls, or females (or for men, boys, or males) are designated by sex and not identity.

It also used the gametic definition of sex:

“Female” means a person belonging, at conception, to the sex that produces the large reproductive cell.

“Male” means a person belonging, at conception, to the sex that produces the small reproductive cell.

. . . and specified standardized terminology:

“Women” or “woman” and “girls” or “girl” shall mean adult and juvenile human females, respectively.

“Men” or “man” and “boys” or “boy” shall mean adult and juvenile human males, respectively.

Of course many people were angered by this, some assuming—with some justification—hat this was more than just a clarification of how sex was to be used in by government, but also an attack on those who considered themselves to not be of male or female gender, or on transsexual people.  I recognize this construal and see that it comes from how people have seen Trump previously comment on sex and gender.

Nevertheless, I think the document itself is pretty much okay, though I can’t see why you can’t have both natal sex and some indication of gender on government documents, although that would be nearly impossible as there are a gazillion genders, and a single character wouldn’t say much. I do appreciate the attempt to protect “women’s spaces.”

Now, in an attempt to further clarify how biological sex is defined, and deal with some of the caveats and misconceptions about it, the Department of Health and Human Services (now headed by RFK Jr., oy), has issued another short document, which you can access below by clicking on the headline or by going here. 

I’ll reproduce the entire text, indented, below the header:

Background

President Donald Trump issued Executive Order 14168 on January 20, 2025, entitled “Defending Women from Gender Ideology Extremism and Restoring Biological Truth to the Federal Government,” which directs the Department of Health and Human Service (the Department) to promulgate clear guidance to the U.S. Government, external partners, and the public, expanding on the sex-based definitions set forth in the Executive Order.

Defining Sex

There are only two sexes, female and male, because there are only two types of gametes. An individual human is either female or male based on whether the person is of the sex characterized by a reproductive system with the biological function of producing eggs (ova) or sperm.

The sex of a human, female or male, is determined genetically at conception (fertilization), and is observable before birth. Having the biological function to produce eggs or sperm does not require that eggs or sperm are ever produced. Some females or males may not or may no longer produce eggs or sperm due to factors such as age, congenital disorders or other developmental conditions, injury, or medical conditions that cause infertility.

A person’s sex is unchangeable and determined by objective biology. The use of hormones or surgical interventions do not change a person’s sex because such actions do not change the type of gamete that the person’s reproductive system has the biological function to produce. Rare disorders of sexual development do not constitute a third sex because these disorders do not lead to the production of a third gamete. That is, the reproductive system of a person with such a disorder does not produce gametes other than eggs or sperm.

The Department has long recognized that the biological differences between females and males require sex-specific practices in medicine and research to ensure optimal health outcomes and rigorous research, including by considering sex as a biological variable.

Recognizing the immutable and biological nature of sex is essential to ensure the protection of women’s health, safety, private spaces, sports, and opportunities. Restoring biological truth to the Federal government is critical to scientific inquiry, public safety, morale, and trust in government itself. Accordingly, the Department promulgates the following definitions:

Definitions

Sex is a person’s immutable biological classification as either male or female.

Female is a person of the sex characterized by a reproductive system with the biological function of producing eggs (ova).

Male is a person of the sex characterized by a reproductive system with the biological function of producing sperm.

Woman is an adult human female. Girl is a minor human female.

Man is an adult human male.

Boy is a minor human male.

Mother is a female parent.

Father is a male parent.

I really cannot find anything biologically wrong with this short document, regardless of what you think its motivations are. And it does provide a standardized terminology while also correcting some misconceptions about sex (a common but ludicrous one is that if you have the reproductive apparatus of, say, a woman, but cannot produce gametes—as in the case of a sterile or postmenopausal woman—you are not a woman). It also notes, correctly, that “Rare disorders of sexual development do not constitute a third sex because these disorders do not lead to the production of a third gamete. That is, the reproductive system of a person with such a disorder does not produce gametes other than eggs or sperm.”  (Many prefer to say “differences of sexual development” rather than “disorders of sex development” because the former sounds less perjorative. I am fine with “differences.”)

It appears that there was some salubrious biological expertise that went into the confection of this document. As I said, I can’t find anything wrong with it, and it comports pretty well with what I see as the consensus of biologists and with how terminology is used in the literature (see another post by Richard Dawkins to come today).  But remember that administrations come and go, and were a semi-progressive Democrat like Biden to be elected again, this document would be very different.

Finally, I cannot resist a bit of snark.  First note that the Society for the Study of Evolution (SSE), the American Society of Naturalists (ASN), and the Society of Systematic Biologists issued a declaration addressed to President Trump and all the members of Congress (declaration archived here), a statement deliberately aimed at contradicting the first Executive Order by declaring that sex is not binary but a spectrum—in all species!  I and others have pointed out the fallacies and misrepresentations in this “tri-societies” letter (see my posts here, here, and here); it almost seems that some of Societies’ misrepresentations of biology were based not on science but on ideology, and were deliberate.

How embarrassing is it, given the situation, that the SSE, the AASN, and the SSB got their biology wrong while the Trump administration got it right! But that’s what happens when scientific societies get ideologically captured.