executive order misstates facts about sex and gender, scientists say

Definition likely to encounter intensive problems in enacting it in the courts and in law

Protesters on the steps of the Cranston Library in Rhode Island while Independent Women's Network hosts a meeting voicing the anti-trans, anti-CRT, and anti-LGBTQ movement, with guest speaker Chris Elston, known as "Billboard Chris." Matthew J. Lee/Globe Staff

President Trump’s executive order recognizing only two sexes — male and female — includes language that is biologically inaccurate and erases trans, nonbinary, and intersex people from federal recognition, according to experts.

The order, signed last week, defines a female as “a person belonging, at conception, to the sex that produces the large reproductive cell.” Male, according to the order, means ”a person belonging, at conception, to the sex that produces the small reproductive cell."

While it’s true that humans are capable of producing just two types of reproductive cells — eggs and sperm, the former thousands of times larger than the latter — the expression of human sexual traits goes well beyond reproductive cells and is anything but binary, said Sarah Richardson, a historian of science at Harvard who specializes in women, gender, and sexuality.

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When describing the diversity of human sexual traits, some biologists refer to the “3Gs”: genes, gonads, and genitals, said Meredith Reiches, a founding member of the Harvard GenderSci Lab.

The only G determined at conception are genes, which in this context refers to sex chromosomes. The vast majority of human embryos are conceived with either XX or XY chromosomes, associated with females and males, respectively. However, in rare cases, people can possess other combinations.

For example, 47,XYY syndrome, also known as Jacobs syndrome, is associated with above-average height and an increased risk of learning disabilities. Another example, 47,XXY syndrome, also known as Klinefelter syndrome, is linked to infertility and underdeveloped, poorly functioning testes, among other symptoms, said Reiches.

“Biologists tend to think of biological sex as more of a recipe with various parts to it. Often, those parts exist in ways that are consistent with popular understandings of male or female, but you also have variation,” said Reiches.

Gonads are organs, such as ovaries and testes, that produce reproductive cells. Humans may possess one or the other, or, in rare cases, both.

“Just because you know what’s going on with someone’s genes doesn’t necessarily mean you can predict what their gonads or external genitalia will look like,” said Reiches.

For example, those with complete androgen insensitivity syndrome possess XY chromosomes, but because their bodies don’t respond to androgens (hormones associated with male development), they’re born with female genitalia, are usually assigned female at birth, and raised as girls. However, they also typically possess internal testes and cannot menstruate or become pregnant.

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Complicating things further, the testes of individuals with complete androgen insensitivity syndrome don’t produce sperm in most cases. Since these people’s bodies do not produce any reproductive cells, Reiches asks: Where do they fall within Trump’s narrow sexual binary? What prisons, single-sex schools, shelters, sports teams, and gender-specific government services do these individuals have a right to?

Richardson said she was unsurprised by this executive order’s redefinition of the sexes because it follows a years-long trend on the right to mask retaliation against the advancement of trans rights behind the façade of “biological truth,” in the words of the executive order.

“This definition is likely to encounter intensive problems in enacting it in the courts and in law due to its incommensurability with medical and scientific knowledge and practice,” said Richardson.

While the vast majority of people do identify with the sex assigned to them at birth, an estimated 2 percent of the country, or more than 6 million Americans, do not fall within these binary definitions, according to interACT, an intersex advocacy organization.

“Under a Trump-style executive order, folks in this situation would be assigned a sex that has nothing to do with how they’ve lived their lives, how they understand themselves, or how the medical establishment has understood them,” said Reiches.

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Nathan Metcalf can be reached at nathan.metcalf@globe.com. https://www.bostonglobe.com/2025/01/28/metro/gender-at-conception-trump/