In 2023, students protested against a new policy in Texas, where parents would be notified if their child asks to be identified as transgender.Credit: Brett Coomer/Houston Chronicle/Getty
This week, Nature is launching a collection of opinion articles on sex and gender in research. Further articles will be published in the coming months. The series will highlight the necessity and challenges of studying a topic that is both hugely under-researched and, increasingly, the focus of arguments worldwide — many of which are neither healthy nor constructive.
Some scientists have been warned off studying sex differences by colleagues. Others, who are already working on sex or gender-related topics, are hesitant to publish their views. Such a climate of fear and reticence serves no one. To find a way forward we need more knowledge, not less.
We need more-nuanced approaches to exploring sex and gender in research
Nearly 20 researchers from diverse fields, including neuroscience, psychology, immunology and cancer, have contributed to the series, which provides a snapshot of where scholars studying sex and gender are aligned — and where they are not. In time, we hope this collection will help to shape research, and provide a reference point for moderating often-intemperate debates.
In practice, people use sex and gender to mean different things. But researchers studying animals typically use sex to refer to male and female individuals, as defined by various anatomical and other biological features. In studies involving humans, participants are generally asked to identify their own sex and/or gender category. Here, gender usually encompasses social and environmental factors, including gender roles, expectations and identity.
For as long as scientific inquiry has existed, people have mainly studied men or male animals. Even as recently as 2009, only 26% of studies using animals included both female and male individuals, according to a review of 10 fields in the biological sciences1. This bias has had serious consequences. Between 1997 and 2000, for instance, eight prescription drugs were removed from the US market, because clinical testing had not revealed women’s greater risk of developing health problems after taking the drugs.
The tide, however, is turning. Many journals, including those in the Nature Portfolio, and funders, such as the US National Institutes of Health, have developed guidelines and mandates to encourage scientists to consider sex and, where appropriate, gender in their work.
Male–female comparisons are powerful in biomedical research — don’t abandon them
These efforts are reaping benefits2. Studies, for example, are showing that a person’s sex and/or gender can influence their risk of disease and chances of survival when it comes to many common causes of death — including cardiovascular conditions and cancer.
Despite this, many researchers remain unconvinced that the inclusion of sex and gender information is important in their field. Others, who are already doing so, have told Nature that they’re afraid of how their work is perceived and of how it could be misunderstood, or misused.
Because researchers who are exploring the effects of sex and gender come from many disciplines, there will be disagreements. An often-raised and valid concern, for example, is that when researchers compare responses between female and male animals, or between men and women, they exclude those whose sex and/or gender doesn’t fall into a binary categorization scheme. Another is that variability between individuals of the same sex could be more important than that between sexes.
Sometimes sense does seem to get lost in the debates. That the term sex refers to a lot of interacting factors, which are not fully understood, does not invalidate its usefulness as a concept3. That some people misinterpret and misuse findings concerning differences between sexes, particularly in relation to the human brain, should not mean denying that any differences exist.
Tempering the debate
Many of the questions being raised, however, are important to ask, especially given concerns about how best to investigate biological differences between groups of humans, and the continued — and, in some regions, worsening — marginalization of people whose sex and/or gender identity doesn’t fall into narrowly defined norms. Often, such questions and concerns can be addressed through research. For example, studies might find that variability between individuals of the same sex in diet, or body weight, say, are more important predictors of how likely they are to develop anaemia than whether they are male or female.
The fraught quest to account for sex in biology research
The problem, then is not the discussions alone: science exists to examine and interrogate disagreements. Rather, the problem is that debates — and work on sex and gender, in general — are being used to polarize opinions about gender identity. As Arthur Arnold, a biologist at the University of California, Los Angeles, and his colleagues describe in their Comment article, last September, legislation banning gender-affirming medical care for people under 18 years old was introduced in Texas on the basis of claims that everyone belongs to one of two gender groups, and that this reality is settled by science. It isn’t. Scientists are reluctant to study sex and gender, not just because of concerns about the complexity and costs of the research, but also because of current tensions.
But it is crucial that scholars do not refrain from considering the effects of sex and gender if such analyses are relevant to their field. Improved knowledge will help to resolve concerns and allow a scholarly consensus to be reached, where possible. Where disagreements persist, our hope is that Nature’s collection of opinion articles will equip researchers with the tools needed to help them persuade others that going back to assuming that male individuals represent everyone is no longer an option.