You’ve heard the excuse before, probably from your mom when she was trying to comfort you about a boy who made you feel sad. “It’s not your fault, honey! He’s a boy, and their brains just work differently than ours do.” We use it all the time to explain a difference in opinions, attitudes, or behaviors between the genders, telling ourselves that male brains work a certain way and female brains work a certain way and that these ways are different. Turns out your mom was wrong.

A recent study by Daphna Joel of Tel-Aviv University has, using MRI technology, determined that structurally there is no real difference between the brains of males and females. The study determined that although specific areas of the brain show sex differences, an individual brain itself is rarely composed of all “male” or all “female” traits.

In reality, it’s much more of a mixed bag approach. Researchers used MRI scans to over 1,400 brains. They looked at variable anatomy-related traits like tissue thickness or volume in different parts of the brain, focusing on traits that showed the biggest sex differences. Doing thing, they were able to divide scores for each traits into a predominantly male zone, a predominantly female zone, and an intermediate range.

Researchers were surprised to discover that less than 6% of of brains across several different data sets actually fell within the predominantly male or predominantly female range. The vast majority scored in of a hodge-podge of “male” and “female” zones.

So what does this mean? Essentially what they’ve determined is that human brains don’t belong to one of two distinct categories. There is no such thing as a “male brain” and a “female brain”, each brain is unique and most are made up of both male and female components. Although gender obviously has a huge impact on the way the brains of each sex works, it turns out it has very little impact on their varying mixtures of male and female anatomical traits. Pretty interesting, huh?