Colors indicate the volumes of brain regions: green indicates large, and yellow indicates small. Image credit: Courtesy of Zohar Berman and Daphna Joel

A new study dispels the myths that there’s anything fundamentally different about men's and women’s brains. In fact, most people have some sort of mix of brain features typically categorized as “male” or “female,” researchers from Israel, Germany, and Switzerland found. 

The study, published in the journal PNAS, argues that if there were really such a thing as male and female brains, there wouldn’t be much overlap in the characteristics of the two—people would show either only male or only female characteristics. However, after examining the brains of 1400 people aged 13 to 85 years old in terms of their composition of gray matter, white matter, and connections, the researchers found that very few people were clustered on the extreme ends of the spectrum of features typically associated with males and females. Rather, there was a lot of overlap. While some features were more common in female brains and others in males, most people have a mix of the two. 

The science of sex differences in the brain is complicated, and hotly debated. Previous studies have indicated that men and women might have different proportions of white and gray matter in their brains or differences in how regions of their brains are connected. One study published in 2014 claimed these differences in functional connectivity underlie superior performance on spatial tasks in men and emotional recognition skills in women. Others argue that these differences are minuscule at best, and many studies subtly reinforce gender stereotypes through poor design, like not taking into account the varied experiences of the men and women tested, such as whether different hobbies or education might underlie their performance on social cognition or spatial processing tasks. 

Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain,” the current study’s authors write. “[W]e should shift from thinking of brains as falling into two classes, one typical of males and the other typical of females, to appreciating the variability of the human brain mosaic.” 

[h/t New Scientist]