Listening to Trans and Nonbinary People: Science cannot yet tell us what determines sex and gender

Note: This post originally appeared on Psychology Today.

As  49 U.S. states rushed to introduce more than 500 pieces of legislation to limit care and discussion of transgender and nonbinary people, it is important  to attempt to understand what all of these bills are trying to accomplish. Many of them restrict affirmative gender care for children and adolescents, with the claim that they would protect youth from prematurely making decisions about their sexual and gender identification.

Of course, we always want to be cautious when administering any medical intervention to children. Developing bodies may be sensitive to medications in ways that adult bodies are not, for example. At the same time, early intervention in situations that may not be as remediable once a body is developed is also important. The critical questions become whether we know the biological basis for gender identification, to what extent gender affirming care is safe and effective, and what transgender and nonbinary people tell us about their experiences.

Chromosomes and Genes Cannot Explain Gender Orientation

People who oppose affirmative gender care sometimes insist that everyone is either male or female. Of course, this is not true. Sex is usually determined based on external characteristics that correlate with the presence or absence of X and Y sex chromosomes. At birth, most infants have either two X chromosomes and have external characteristics traditionally associated with being  female or an X and a Y chromosome and have external characteristics traditionally associated with being male. But this is not always the case. For instance, about  1 in 2,500 newborn females have only one X chromosome, called Turner’s syndrome. Girls with Turner’s syndrome usually exhibit short stature and  cannot conceive spontaneously. A child can be born with two X chromosomes and one Y chromosome (XXY), a condition known as Klinefelter syndrome, which occurs in about 1 in 600 live male births. There are a variety of other variations from the typical XX/XY sex chromosome pattern, leading to different physical and emotional consequences. Hence, simply knowing someone’s chromosomal pattern tells us very little about whether they will feel male or female and  scientists have been cautioned against tying genetic information to gender orientation or treating sex as a binary variable.

 If it is incorrect, then, to assume that sex chromosomes determine biological sex or gender identification, perhaps it is something in the brain that makes this distinction. Indeed, researchers have looked for differences in brain anatomy and function among people expressing various sexual and gender identities. In a moving op-ed piece in the  Washington Post, Jennifer Finney Boylan, an English Professor at Barnard College of Columbia University and fellow at Harvard University who is openly trans, concluded that “What the research has found is that the brains of trans people are unique: neither female nor male exactly, but something distinct.” When we looked at one of the papers that Boylan cites to support this conclusion, however, we noted that it used a magnetic resonance imaging (MRI) method of characterizing the physical structure of brains as either male or female that is not universally accepted. In fact, most scientists would agree that there is very little known at this time that helps us distinguish “male” from “female” brains. If you ask an expert to look at the MRI of a brain it is impossible to determine whether that brain is inside the head of a man or woman.

Asking People How They Feel Is Our Current Best Evidence

So, if we cannot use sex chromosomes or brain anatomy to tell us who is male and who is female, our best method is to ask people how they feel. Returning to Professor Boylan, we have testimonies like  this:

No one who embarks upon a life as a trans person in this country is doing so out of caprice, or a whim, or a delusion. We are living these wondrous and perilous lives for one reason only — because our hearts demand it. Given the tremendous courage it takes to come out, given the fact that even now trans people can still lose everything — family, friends, jobs, even our lives — what we need now is not new legislation to make things harder. What we need now is understanding, not cruelty. What we need now is not hatred but love.

Increasingly, interviews and surveys with trans people tell us several things. First, that people often recognize they have been assigned the wrong sex at birth at a very early age. Second, that trans youth who do not undergo gender affirming care have high rates of depression and suicidal ideation and suicide attempts. Third, that most trans people who undergo gender-affirming care do not regret doing so.

The Washington Post recently ran a series of articles on trans and nonbinary people based on a  survey they conducted with the Kaiser Family Foundation. One  finding of the study was that “1 in 3 transgender adults was 20 years old or younger when they began to understand that their gender was different from their sex assigned at birth.” Interviews and polls like this suggest that trans people often  recognize early on that the sex assigned to them at birth was incorrect and that this was not due to influence from anyone else but rather to a recognition of how they feel.

Studies have consistently shown that trans and nonbinary youth have high rates of depression and suicidal ideation, in part because of bullying and social ostracism. But treatment with puberty blockers and gender-affirming hormones (GBH) results in  marked improvement in mental health outcomes.  

When the Washington Post surveyors interviewed middle-aged trans people, they found that: “All said they felt relief once they made their transition.” Derek P. Siegel, a PhD candidate in sociology at the University of Massachusetts, Amherst, wrote in  The Conversation that “From 2019 to 2021, I interviewed 54 transgender women—both current and prospective parents—from diverse racial and class backgrounds across the country. I found that while many have navigated discrimination in their parenting journeys, they also have fulfilling parent-child relationships, often with the support of partners, families of origin and their communities.” We need more systematic data on this, but at present evidence suggests that people do not regret having  gender-affirming treatments, including  transition surgery.

Laws Against Gender-Affirming Care Don’t Prevent Harm

The  Washington Post-Kaiser Family Foundation survey found that “Most Americans don’t believe it’s even possible to be a gender that differs from that assigned at birth. A 57 percent majority of adults said a person’s gender is determined from the start, with 43 percent saying it can differ.” We know that this is not true in the case of people born with different chromosomal patterns, who may appear to be one sex externally but have chromosomes and even organs of a different sex. Medical science has long known that it is possible to be a different sex than the one assigned at birth. That, however, is only part of the story because we are also learning that we know surprisingly little about what actually determines a person’s “true” sex and/or gender. It is not in any known genetic pattern, nor are there any reliable signals from brain anatomy or function that tell us who is a “male” and who is a “female.” When we talk to people, then, we get our best current information.

Right now, we know that approximately  0.6 percent of the American population over the age of 13 identifies as trans or nonbinary. That’s about 1.6 million people in the U.S. alone. What we also know is that many of them recognize early on they were not assigned the correct gender at birth, that they suffer significant emotional harm if not offered gender-affirmative care, and that when they do take advantage of interventions like puberty blockers and gender-affirming hormones they have improved mental health and life satisfaction outcomes. Laws that limit care for trans and nonbinary people, both adults and children, would seem to be far away from protecting them from harm. We should follow the data we have and offer people who identify as trans and nonbinary evidence-based help and support.