Study: Forensic Anthropology’s Sex Estimation Methods Ignore Trans, Intersex People

Bones Don’t Lie, But Forensic Anthropology’s Sex Methods May Not Tell the Whole Truth

When a forensic anthropologist examines a skeleton, one of the first questions they look to answer is if the person was male or female. Now, a new paper argues the field has been asking the wrong question for decades, and that trans, intersex, and gender-diverse individuals are paying the price.

Published in the Annual Review of Anthropology, the review by Sean Tallman of Boston University and Donovan Adams of the University of Central Florida argues that forensic anthropology’s view of biological sex is too narrow, and that an early alliance with the FBI in the 1930s pushed the discipline toward clean, court-ready answers at the expense of scientific accuracy.

Forensic anthropologists build a “biological profile” from skeletal remains, estimating sex, age, stature, and ancestry, with sex often treated as the starting point because many other estimates have traditionally been built around female/male categories. Tallman and Adams argue those methods were built almost exclusively on skeletons of cisgender, non-intersex individuals, inside a field long dominated by white, cisgendered male practitioners.

Why Forensic Anthropology Sex Estimation Has a Binary Problem

Central to the critique is something the authors call “biological normalcy,” a feedback loop in which research methods and cultural expectations reinforce each other. Forensic textbooks have long shown side-by-side images of extremely “typical” female and male skulls and pelvises, making it look as though human skeletons sort cleanly into two groups. On actual skeletal material, the variation is far messier.

Updated terminology hasn’t fixed this. Words like “gracile” (small-framed) and “robust” (large-framed) replaced older language like “feminine” and “masculine,” but still imply only two body types exist. A recent survey found that 22% of forensic anthropologists still describe skeletal traits as “feminine” or “masculine,” and 10% still use pronouns like “she/her” or “he/him” in official case reports.

Tallman and Adams also take aim at a 2012 textbook chapter in a book that appears on the 2026 reading and competencies list for certification through the American Board of Forensic Anthropology. In it, the authors invoked Marilyn Monroe’s physique and Sigourney Weaver’s frame in the film Alien to claim that humans are “natural-born sex assessment experts.” Tallman and Adams describe this as the same logic behind transphobic online conspiracy theories that claim you can identify someone’s birth sex from their body. That the textbook still appears on a certification reading list says plenty about the field’s pace of change.

Trans and Intersex Individuals Are Missing From Sex Estimation Research

No sex estimation study has ever knowingly included transgender or intersex people. Body donation programs rarely offer those options on intake forms, so intersex individuals may already sit in skeletal reference collections coded simply as female or male, blurring the data behind some of the field’s core methods.

Intersex people, who account for roughly 2% of the population, are almost never mentioned in forensic anthropology training materials. One 2012 textbook passage dismissed them as too rare to matter, then posed what its authors called a simple question: “the question in sex determination remains very simple: was it a ‘he’ or a ‘she’?”

For transgender people, the problem is related but distinct. Because standard methods were built around skeletons coded as female or male, usually without information about gender identity, they may point investigators toward sex assigned at birth rather than the person’s lived identity. Current professional standards hold that “gender cannot be determined from skeletal remains,” a rule Tallman and Adams argue throws out contextual clues that may be the only way to identify a trans person who dies under unclear circumstances.

Away from the lab, the damage goes wider. Social media influencers on TikTok and YouTube have seized on forensic anthropology’s binary framing to claim that bone analysis proves trans and intersex identities aren’t real. Tallman and Adams tie that misuse directly to the field’s failure to modernize.

850 Anti-LGBTQ+ Bills Put Forensic Anthropology Sex Estimation in a Political Spotlight

Tallman and Adams frame their paper against the current political moment. More than 850 anti-LGBTQ+ bills and executive orders were filed in the U.S. in 2025 alone, many seeking to legally define sex as strictly binary. Co-author Adams works at the University of Central Florida under a Florida statute barring courses from teaching anything interpreted as “identity politics” or DEI-related, and his own research underwent state review in 2023. In light of all this, the authors write, “those of us who can, should intensify advocating for science, marginalized groups, and productive disciplinary/self-critique.”

One statistical approach, called fuzzy logic, may help researchers describe overlap instead of forcing every skeleton into one of two boxes. In one recent analysis of skull data, researchers found as many as six clusters of sex-related variation, a sign that the usual binary categories may be too blunt. Tallman and Adams point to it as the direction the field should be moving.

Forensic anthropology has already been forced to reexamine ancestry and race estimation methods built on racially biased assumptions. Tallman and Adams are arguing that sex estimation deserves the same hard look.

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Disclaimer: This article is based on a critical review paper and reflects the authors’ analysis and arguments. It does not constitute legal, medical, or forensic guidance.

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