Social scientists and gender theorists have long debated the causes of achievement disparities between males and females in certain competencies. For example, if we find (as we do) that most engineers are males and most nurses are female, would we attribute this disparity to innate sex differences in ability (males are better at math; women are better at relational empathy), interest (man are more interested in numbers; women are more interested in people), or to the social traditions and expectations, which serve to shape and channel males and females into different social niches (nursing is feminine; math is masculine)?
The answer to this question has concrete implications. If sex differences are mostly due to social pressures and expectations, then changing those social constructs should lead to the reduction of such disparities. Indeed, such was the hope of many gender theorists as 20th-century scholars began deconstructing the cultural gender narrative. Social constructivist theories have long predicted that sex differences will decline in more gender equal countries. A thrust of the feminist theory was thus aimed at opening the definitions of what constitutes male and female, relaxing old, rigid cultural constrictions, and providing equal access across the board to educational and professional opportunities. If nursing is no longer considered unmanly, and if engineering is no longer considered unfeminine, and if girls and boys are taught from an early age that both fields are equally open and acceptable to them and are given equal role models and social support to those ends, then we will see a de-gendering of the professions.
Alas, this is not what actually happened.
For example, around the Western world today, women tend to outnumber and outperform men in higher education. Norms have relaxed and expanded, opportunities have increased, barriers have been removed, and the social playing field has all but been leveled. Yet women are still underrepresented in STEM fields.
Moreover, such differences have been shown to increase in gender-equal countries. This has come to be known as the gender equality paradox. Research has shown that “adolescents’ aspirations to enter sex-typical occupations (people-oriented for girls, things-oriented for boys) were highest in gender-equal countries like Finland, Norway, and Sweden and lowest in Indonesia and Morocco.”
Why would that be? First, psychologists theorize that in stressful environments (frequent nutritional shortfalls, disease risk, etc.), sex differences are attenuated because the effects of those stressors are more apparent in the sex where the trait is greater. For example, if women are predisposed toward better longevity, harsh conditions are going to hinder their ability to express their full longevity potential. Moreover, under these harsh conditions, societies tend to become more restrictive of individual expression. Harsh environments, in other words, work to diminish inborn sex differences. Conversely, if quality of life improves and stressors diminish, social restrictions tend to lessen, allowing a fuller expression of individual—and sex—differences in various domains.
In other words, say I have the potential, under optimal conditions, to grow to 10 feet tall, while your potential is to grow to 5 feet tall. Say that stress takes away 20 percent of our potentials. I will end up at 8 feet, and you will be 4 feet tall. The difference between us is smaller under stressful conditions.
Recently, another factor has been shown to operate in this area—sex differences in intraindividual academic strengths, which refers to a student’s best academic subject (mathematics, reading, or science), regardless of their overall academic achievement. Research has shown that females tend to have intraindividual strengths in reading, while males tend to have intraindividual strengths in mathematics or science.
Motivation theorists have proposed several models seeking to explain how motivation influences choice, persistence, and performance. One such perspective is expectancy–value theory, which argues that “individuals’ choice, persistence, and performance can be explained by their beliefs about how well they will do on the activity and the extent to which they value the activity.” According to this framework, students’ comparative advantage (i.e., intraindividual academic strengths) influences educational choices by shaping their expectations (the likelihood of doing well in a given subject) and the value (anticipated long-term benefits) of choosing these subjects.
This framework predicts that students whose best subject is math would be more likely to enroll in STEM fields in college, because they expect to do well. Those whose best subject is reading would end up in the humanities or social science classes, expecting to excel there. This prediction has found support from large-scale longitudinal studies in the United States and abroad.
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The bulk of the research to date on this phenomenon has relied on average performance indices. This approach fails to answer the question of whether similar patterns exist among students at the highest and lowest levels of academic achievement. This is important because the gender equality paradox might be more relevant for high achievers, given the intellectual demands of STEM fields. In such environments, a pronounced gender equality paradox would explain why fewer women enter STEM fields.
A recent (2025) large study by Finnish researcher Marco Balducci and colleagues sought to answer this question. The authors examined sex differences in intraindividual academic strengths using data from 1.6 million adolescents across 82 countries and regions for three waves (2012, 2015, and 2018) of the Programme for International Student Assessment (PISA) among high (95th percentile), average (> 5th to < 95th percentile), and low (5th percentile) achievers.
Results showed that girls’ and boys’ characteristic intraindividual strength (in reading and mathematics/science, respectively) remained stable across countries, waves, and achievement levels. In countries where boys had larger advantages in mathematics or science, girls had an even larger advantage in reading scores. Moreover, as expected given the gender equality paradox, “the magnitude of the sex differences in reading and science as intraindividual strengths increased with increases in national gender equality at each PISA achievement level.”
Finally, the authors’ findings support the conclusion that, at the level of society, egalitarian gender norms encourage individuals of both sexes to develop pre-existing strengths. “As national gender equality increases, the sex with an overall advantage improves on their intraindividual strength, while the sex with an overall disadvantage shows a decline.” Thus, the equality paradox.
The authors conclude: “The broad pattern of sex differences in intraindividual academic strengths across achievement levels, countries, and PISA waves, as well as their increase for reading and science in more gender-equal countries, makes intraindividual strengths a plausible contributor to sex differences in some STEM fields.”
