Critics claim trans people ‘defy biology.’ New research suggests otherwise
[post_content]
Disclaimer: This article has been automatically aggregated from
Public debate surrounding transgender and gender-diverse (trans) people often centers on one fundamental question: What makes someone trans?
Most of us would agree that our gender is not a choice but a core part of who we are. When our gender aligns with the sex listed on our birth certificate, it’s rarely questioned. Instead, it’s treated as a biological reality.
However, when it comes to trans people, an alternative explanation is frequently floated: that trans identities and gender diversity are the result of environmental influences, such as social trends or peer pressure.
This framing treats a trans identity as a choice that can—and, implicitly, should—be unlearned.
Such messaging is increasingly being used to deny the existence of trans people, restrict access to medically necessary health care and fuel discrimination.
Our study of twins challenges this idea and shows that the likelihood of being trans is influenced by genes.
The power of twin studies
Twin studies are a powerful tool in research. Identical twins share 100% of their genes, whereas nonidentical twins share 50% on average—the same as nontwin siblings.
By comparing these two types of twins, we can explore the extent to which genetics and the environment contribute to human traits.
If genes are involved, we expect identical twins to share traits (for example, both identifying as trans) more often than nonidentical twins, simply because of their greater genetic similarity.
Conversely, if genes aren’t involved, we expect to see similar rates of shared traits among identical and nonidentical pairs.
Our research examined data from 463 twin pairs in which at least one was trans—the most comprehensive analysis on this topic to date.
After determining whether twin pairs were identical or nonidentical, we measured how often both twins were trans and compared this with instances in which only one was trans.
What we found
Our results showed that among identical twins, if one was trans, the likelihood that the other was also trans was 21.2%.
For nonidentical twins, this rate was significantly lower, at 8.7%—though this was still well above the 1–2% prevalence of trans identities in the general population.
Nontwin siblings weren’t included in our research, but we’d expect their rate to be similar to that seen among nonidentical twins.
If being trans were purely a social phenomenon, we would not see this stepwise difference, in which the chance of being trans increases with genetic similarity.
Our data thus provide strong evidence that genes are involved.
More than just genes
It’s also important to highlight another finding in our data: Most twin pairs, even among those who are identical, are not both trans.
This comes as no surprise to researchers who study twins, who have documented similar patterns for many other human traits.
Almost all human traits, such as personality characteristics, height and sexuality, are shaped by both genetic and environmental factors.
It’s likely that gender identity is the same.
Interplay of genetics and the environment
Genes and the environment do not act independently, and the influence of genetics on any complex human trait does not stem from variations in a single gene.
Rather, hundreds or even thousands of genes work alongside and interact with environmental influences to form an enormous range of human characteristics.
Environmental factors can affect the activity of our genes throughout our lives. Such environmental influences encompass the full breadth of human experiences, all the way back to conception.
Both identical and nonidentical twins share environmental experiences, especially in the womb and as children raised together in the same family.
But each twin also has unique experiences that contribute to their individual differences. So, it really is a complex interplay between genes and the environment.
Why this matters for public understanding
Many anti-trans arguments rely on a belief that gender diversity is entirely socially determined.
This myth is frequently weaponized to frame trans identities as optional or reversible. Too often, this becomes a justification for hostile public attitudes and for stripping basic legal protections from trans people.
The belief that being trans is purely a social phenomenon also provides a rationale for harmful identity change and suppression practices (also known as conversion therapy).
Every major Australian and U.S. medical association has condemned these practices.
However, a recent U.S. Supreme Court case and other national and state policy developments in the U.S. are increasingly providing cover for those performing these harmful practices.
A complex and enduring human trait
Our findings provide a crucial correction to this harmful public discourse. They confirm that genes and their related biological pathways play a role in shaping gender identity.
Fears of trans identities being a social trend or response to peer pressure—and related shifts in policies to restrict trans people’s basic rights—are at odds with the scientific evidence.
Gender diversity has existed across millennia and is an inherent part of human diversity. It’s time law and society caught up.
Provided by
The Conversation
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Citation:
Critics claim trans people ‘defy biology.’ New research suggests otherwise (2026, August 31)
retrieved 31 August 2026
from https://phys.org/news/2026-08-critics-trans-people-defy-biology.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.
for informational purposes only. We do not claim ownership, accuracy, or liability for the content provided. All rights belong to the original publisher.