According to the American Association of University Women, women make up only 28% of the workforce in science, technology, engineering and math, or STEM. According to a new study from Michigan State University published in the journal American Economic Association Papers & Proceedings, one source of this gap may arise in early childhood. The authors argue that women may be more likely to develop an early interest in non-STEM fields.

“People tend to pursue what they’re already good at. We find that among young children, girls outperform boys in reading but not in math. If this early advantage steers girls into pursuing more reading-related subjects in elementary and middle school, more of them may choose to pursue the humanities or related fields in college,” said co-author Amanda Chuan, assistant professor in the School of Human Resources and Labor Relations within the College of Social Science.

The researchers use a longitudinal study that tracked the same 953 children for 12 years. They find that among children as young as 3-7 years old, girls scored significantly higher than boys in standardized reading tests. However, there was no such gap in math.

One reason for girls' early advantage may stem from parental involvement. The researchers found that the time parents spent teaching their 3 to 5 year olds predicted their children's reading test scores at ages 8 to 14. Importantly, parental teaching was a far better predictor of reading than math scores. The researchers conjecture that at young ages, teaching language arts may be more natural for parents than teaching math. Chuan adds, "Teaching language arts arises from casually talking to a child, while teaching math concepts may require more effort, such as using blocks to teach shapes or opening a book to teach counting."

The research team also explores why parents may teach more to girls than to boys. Their survey evidence indicated that parents rated girls to be more receptive to teaching. Separate assessments by educators indicated that girls tended to exhibit better self-regulation than boys at early ages, which may make it easier for them to pay attention and cooperate when their parents tried to teach.

The study, “Parental Investments in Early Childhood and the Gender Gap in Math and Literacy,” is authored by Amanda Chuan, John A. List, Anya Samek, and Shreemayi Samujjwala.

The article can be found on the American Economica Association Papers & Proceedings website.

This story originally appeared on the School of Human Resources and Labor Relations website.