Sex and Gender

Disclaimer

The content on this web page explains the University of Iowa Michaelson Lab’s scientific inquiry into the genetic relationships between sex, gender, and neurodevelopment. We recognize that while this research may not reflect current institutional priorities, our ability to conduct and speak upon this work is protected by the Iowa Board of Regents Freedom of Expression Policy Statement, stating “The primary function of the Regent universities is the discovery, improvement, transmission, and dissemination of knowledge by means of research, teaching, discussion, and debate. To fulfill this function, the universities must strive to ensure the fullest degree of intellectual freedom and free expression allowed under the First Amendment to the Constitution of the United States.”

Our goal is to better understand molecular and genetic interplay between sex, gender, and neurodevelopment.

Why This Research?

Biological sex has a strong relationship with neurodevelopmental and psychiatric conditions. For example, more men have autism than women (4:1) and more women have anorexia than men (8:1).^1-2

Recent scientific advances have revealed this relationship isn't as simple as “men are more autistic because they have XY chromosomes” and “women have more eating disorders because they have XX chromosomes.” In fact, many factors related to sex, including sex hormones present in males and females, are involved.³

Gender adds another layer to our investigations. Gender is defined by social and cultural norms related to being a “man” or a “woman,” and can include identities beyond those two categories. Previous research has shown gender identity can be related to psychiatric conditions. For example, autism is more common in transgender or nonbinary individuals^9-14.

Given the complexities described above, our research uses a continuous (rather than binary) approach to sex and gender to provide biological insights into psychiatric and neurodevelopmental conditions, and more generally into how the brain develops.

Visualizing Sex as a Spectrum

Scientific American has put together a thorough diagram of how sex determination can be visualized as a continuous spectrum, rather than the binary view of XX female and XY male.

A woman and man stand in a cornfield as sun sets

Community Involvement: Considering All Perspectives

We are aware that gender diversity is a sensitive and, at times, heated topic in the current social and political climate. In an effort to respect this sensitivity, we have integrated community involvement into our research.

While we have prioritized the voices of those most likely to be affected by our findings (such as LGBTQ individuals and those with autism spectrum disorder [ASD]), we are interested in the perspectives of all people, regardless of identity or background.

We have already conducted a survey assessing how individuals from various backgrounds (LGBTQ and non-LGBTQ) perceive genetic and mental health research about sex and gender. Our results showed that attitudes towards this research was driven by a variety of factors, including perceptions of science research broadly, tolerance towards the LGBTQ community, and personal identities.

Read the Publication Here

From the survey, we formed a community advisory council (CAC) composed of members from the LGBTQ and ASD communities. This council functions to review all results before publication, so we can develop messaging that is scientifically accurate, but also reduces risks and misinterpretation. Additionally, our research team and other collaborators include scientists who are members of the LGBTQ community.

Most recently, we consulted with a panel of both gender diverse and cisgender individuals to revise a questionnaire related to gender identity (not yet published).

While our first priority is ensuring that the voices of our LGBTQ partners are heard and the risks are minimized, we want to emphasize that as scientists we have no agenda. We form hypotheses based on current knowledge, collect data, and then analyze that data to support or refute our hypotheses.

Our Findings

Given the impact of sex and gender on the presentation of neuropsychiatric conditions, our past and present research aims to clarify the genetic intersection between sex, gender identity, and mental health.

We discovered no significant association between neuropsychiatric polygenic risk and gender diversity measured through the Gender Self-Report for a group of independent adults with autism. These results suggests that there is not a strong genetic overlap between the genetic variants leading to the development of mental health conditions and the genetic variants leading to the development of gender diversity.

Gender Self-Report: First-of-Its-Kind

The Gender Self-Report (GSR) was the first means of deeply capturing an individual's internal experiences of gender and gender diversity. "Prior tools didn't really capture all of the meaningful variation that exists. The GSR instead describes people’s gender using continuous values along several different dimensions. Wherever they exist in that space kind of has a slightly different meaning about their gender identity," says Jake Michaelson, quoted in this story.

Current Projects

We have recently created a rich and intentionally sculpted survey that captures a wide expanse of human experiences, including mental health traits, medical histories, and adverse life events (covering general, gender-related, LGBTQ-specific, and autism-specific stressors).

We are pairing this survey with a newly revised version of the Gender Self-Report, which we are also in the works of validating through a diverse gender, racial, geographical, and political sample.

All questions will be disseminated to 5,000-10,000 individuals with a personal or family history of autism through Spark Research Match.

Our main aim is to explore how adverse life experiences and stressors can affect mental health, with genetics as a potential mediator of those effects.

Note

We recognize that the kinds of nuances in this research are often lost in the process of communicating science to the public. As outlined above, our goal is to mitigate this possibility through a proactive approach to science communication that involves community stakeholders. We cannot guarantee that the results of our research, once in the hands of the public, will remain free of biased interpretation. We hope that by making a research contribution that is both scientifically rigorous and informed by community perspectives, we can minimize the potential risks inherent in this line of inquiry.

Frequently Asked Questions

What's the difference between 'sex' and 'gender' in your research?

It's simple - we use 'sex' to refer to the biological categories of male and female, determined by DNA and physical characteristics. 'Gender' refers to behavior and personality traits (including inner feelings) that typically align with being a man or woman. For most people (about 99%), sex and gender line up naturally, but for some people they don't. Our research acknowledges this reality because good medicine doesn't ignore any American who needs care, no matter how rare their situation might be.

Are sex and gender biological? I can hear one of my college professors saying “gender is a social construct."

Obviously sex is biological because it depends on sex chromosomes (X and Y) as well as how the body responds to its own natural hormones. Gender is the collection of behaviors and personality characteristics that are typical of each sex. We know from previous research that behavior and personality have strong genetic influences, so it makes sense that gender (how behavior and personality relate to sex), and how well you “fit in” is also under genetic influence. So yes, gender can be understood as a social construct – but it also exists in relation to genetic and biological underpinnings.

I feel like sex and gender are the same thing.

That’s not really a question, but your feeling is onto something. For the continuation of our species, there is a strong pull to align our sex with our gender (the sex-typical behaviors and personality traits). Geneticists talk about “selective pressure” as a force that keeps genetic changes in check, and that is at play here. If the human genome changed too quickly and in a way that made most humans completely uninterested in reproducing, those same changes would disappear.

There are only two genders.

Answer forthcoming.

Isn’t all this “gender diversity” stuff just a new fad? Why does it seem like nowadays there are so many people saying they’re trans or nonbinary? It didn’t used to be like this.

Answer forthcoming.

Additional Resources

Key Terms Defined

Throughout our research on sex and gender, we use various terms, many which can be (mis)interpreted differently outside of a scientific context. To provide clarity on key terms, we have listed their definitions below.

neurodevelopment	the continuous process of the formation and maturation of the brain from fetal development through infancy and childhood, puberty and adolescence, and into adulthood
sex	a categorical descriptor based on the generalized reproductive role within a species. For humans, this is inferred at birth from observation of genitalia. While most newborns can be clearly assigned as male or female, some cases (0.1-1.5%) are ambiguous and may be reported as intersex
sex characteristics	indicators of sex, typically divided into primary and secondary categories. These are genetic, biological, physiological, morphological, or behavioral features that are associated with typical male or female development
primary sex characteristics	indicators of sex that are observable at birth, such as genitalia or configuration of sex chromosomes (i.e., karyotype - for example, XX female or XY male, though there are additional possibilities)
secondary sex characteristics	indicators of sex that typically emerge after birth, usually during puberty, and usually with a greater spectrum of variability than primary sex characteristics have. These include changes in patterns of body hair growth, breast and muscle development, distribution of body fat, voice development, sexual attraction, etc.
sexual orientation	indicators of sex that typically emerge after birth, usually during puberty, and usually with a greater spectrum of variability than primary sex characteristics have. These include changes in patterns of body hair growth, breast and muscle development, distribution of body fat, voice development, sexual attraction, etc.
gender	the behavioral norms for each sex that emerge at the population level, driven by a combination of biological, social, and cultural influences
gender identity	the relation of an individual to gender norms that is most consistent with that individual's feelings, perspectives, and behaviors cisgender individuals identify with the gender that is consistent with their biological sex assigned at birth transgender individuals identify with a gender that is different than their biological sex assigned at birth gender non-binary (genderqueer) individuals have a complex gender identity that may reflect some combination of masculine or feminine gender norms, while not conforming to others agender individuals do not identify with any combination of gender norms

Further definitions of LGBTQ+ related terms can be found here:

Additional Questions?

If you have any more questions, please don't hesitate to contact our research team at michaelson-lab@uiowa.edu or at 319.335.8882.

Michaelson Lab