A new scientific paper has argued that evidence from evolutionary psychology, neuroscience, and cross-cultural survey shows that gender is not merely a social construct – highlighting how brain structure and physical differences are formed in males and females while in the womb.
The academic paper, published in the Springer Nature Journal, was written by Marc J. Defant, PhD, a tenured Professor Department of Geology University of South Florida.
The piece critiques the ‘social construct’ accounts of gender, and evaluates the biological and ethical foundations of gender-affirming medical practices.
The paper, which affirms the reality of sex and gender, says the evidence shows that prenatal and postnatal hormone exposures sculpt brain structure and behaviour in predictable and sex-specific ways.
Further, it says that cognitive and physical differences – such as human males’ spatial reasoning advantages and human females’ verbal and empathic strengths – emerge consistently across disparate societies.
The study questions guidelines from the American Psychological Association, which emphasise the role of culture while “disregarding biological underpinnings.”
The American Psychological Association (APA), defines gender as the “socially constructed roles, behaviours, activities, and attributes that a given society considers appropriate for boys and men or girls and women – distinct from sex, which is assigned at birth based on physical attributes.”
The paper, a multidisciplinary review of existing literature and research from evolutionary psychology, neuroscience, economics, and cross-cultural studies, used data from developmental biology, hormonal studies, and behavioural research to evaluate biological differences between human males and human females.
‘STRUCTURAL BRAIN DIFFERENCES BETWEEN MALES AND FEMALES’
These findings were then compared with the claims of social constructionist theorists. Critical analyses of policies and guidelines, such as the APA’s position on masculinity.
The analysis states that biological factors such as hormones, brain structures, and evolutionary processes significantly influence sex and gender.
The author says that the idea that gender – encompassing masculinity and femininity – is a social construct, or that sex and gender exist on a spectrum, lacks scientific support.
“Hormonal influences like testosterone, which shapes male-typical brain organisation and physical traits, and cross-cultural consistencies in sex differences, affirm their biological roots. Efforts to erase these differences through ideological frameworks ignore the complementary strengths human males and human females bring to society, such as human males’ physical prowess and human females’ caregiving capacities,” he found.
“Recognising these biological factors stem from biology does not preclude equality but enhances our understanding of human diversity,” he says.
The paper adds: “Denying biological reality in favor of social constructivism undermines scientific progress and risks harming individuals by dismissing their inherent traits. Acknowledging the evolutionary basis of sex and gender differences fosters respect for individual expression while grounding societal policies in evidence. By celebrating these differences, rather than attempting to homogenize them, we can promote equality of opportunity and dignity for all, ensuring that fields like psychology and biology advance with clarity and integrity.”
It notes that evidence from neuroscience reveals structural brain differences between human males and human females, while studies in developmental biology underscore the impact of prenatal hormone exposure on behavior.
“Cross-cultural research shows consistent gendered behaviors, challenging the assertion that gender is merely a social construct,” it emphasises.
The author states: “Critiques of social constructionism – whether in feminist, philosophical, or institutional contexts like the APA’s guidelines – reveal an unsettling willingness to subordinate empirical reality to ideological commitments.”
Dr Defant writes: “Taken together, these findings refute the core tenets of radical social construction-ism: while culture and socialization undoubtedly influence how gender is expressed or policed, they do not overwrite the deep biological underpinnings of sex and gender.
“Recognising this dual reality – honouring both our shared humanity and our biological diversity – allows us to craft policies, educational programs, and clinical practices that respect individual dignity without disregarding scientific truth.
“Moving forward, it is imperative that we shift our focus away from ideological battles over whether gender is “real” or “constructed,” and instead ground our decisions in rigorous, merit-based inquiry,” he adds.
“Whether we are developing medical guidelines, shaping educational curricula, or debating fairness in sports, our criteria should be evidence and outcome, not political allegiance. By recommitting to a science-first ethos, we safeguard both intellectual integrity and social progress – ensuring that debates about sex and gender are informed by data rather than dogma, and that our collective pursuit of fairness is built on a foundation of fact rather than faction.”
‘WHY DO WE INVOKE SOCIAL FACTORS SO FREQUENTLY?’
Writing in The Skeptic last August, the professor said: “Gender identity has become one of the most pressing–and polarizing–topics in today’s cultural landscape. Major medical associations have embraced a variety of gender-affirming treatments, ranging from counseling sessions to lifelong hormonal therapies and even surgeries.
“Their rationale is that these interventions help alleviate severe distress among people who experience a disconnect between the sex they were born with and the gender they identify as. In the same breath, however, many of these organizations and prominent voices also describe gender as largely a “social construct”–something molded by cultural norms rather than by biology.
“That claim raises a fundamental paradox. If gender truly rests on external expectations, why do some advocates support irreversible medical procedures–especially in children–as a primary response to gender-related distress? On the flip side, if there is a strong biological basis for gender identity, then why do we invoke social factors so frequently?”
He adds: “For parents, policy-makers, and health professionals trying to do right by patients, these questions create a tangle of uncertainty. Even more critically, children and teenagers lie at the center of an ethical storm that involves decisions about their bodies, their long-term health, and whether or not they should receive life-changing medical treatments before they’ve reached adulthood.
“In cases where a teen is diagnosed with gender dysphoria, the stakes are exceptionally high. The potential harm extends beyond immediate side effects: puberty blockers can impact bone density, cross-sex hormones can affect future fertility, and surgeries might remove or alter healthy body parts in a way that can never be reversed.
“If the teen comes to identify differently in later years–as many detransitioners report–the regret can be profound. These individuals sometimes feel they made decisions they weren’t old enough to understand, pointing to mental health struggles, outside influence, or social pressures that contributed to their choices at the time.”
“The research notes that evolutionary forces that exist in society today, have had too short of a duration to impact natural selection, adding that it should be noted that the origin of sexual orientation is still controversial.”
Further, the paper points to how the male world record in archery is better than the female world record, and men tend to have better overall performances in the sport than women.
Moreover, it says that the failure of conversion therapies supports the “biological foundation of sexual orientation.”
“The findings refute the core tenets of social constructionism, affirming the biological reality of sex and gender. While acknowledging the role of culture in shaping gender expressions, the study emphasises the importance of respecting scientific evidence to inform policy and social discourse. A balanced approach that integrates biological and cultural perspectives is advocated, promoting inclusivity without undermining empirical reality,” says the author.