Researchers looked at MRI brain scans of 104 youngsters aged 3 to 10 years old (55 girls and 49 boys) while they were watching a video on basic maths topics. Unsurprisingly, they noticed no significant differences between brain activity across the genders.

Nor was there any noticeable statistical difference between girls and boys in how engaged the kids were in the maths topics presented to them, or in the way the brain was developing in the older children.

"Science doesn't align with folk beliefs," says neuroscientist Jessica Cantlon, from Carnegie Mellon University (CMU).

"We see that children's brains function similarly regardless of their gender, so hopefully we can recalibrate expectations of what children can achieve in mathematics."

Many of us have long since dismissed the myth that girls are less competent at science, technology, engineering and mathematics (STEM), but for those who are still holding on to the idea, these results provide yet more clear evidence.

Most of the brain activity was taking place in the intraparietal sulcus, a region known to be linked with estimating numbers, processing numbers written out as words, and doing addition and subtraction sums.

On top of that, the researchers also used a maths test to grade 97 kids aged between 3 and 8 years old (50 girls and 47 boys), finding that there was no difference in ability between the genders, and no difference in maths ability and brain maturity.

"It's not just that boys and girls are using the maths network in the same ways but that similarities were evident across the entire brain," says psychologist Alyssa Kersey, from the University of Chicago.

"This is an important reminder that humans are more similar to each other than we are different."

It rules out the hypothesis that more males end up in STEM-related careers because they're somehow better at the maths required in some of those fields. Something else must be going on: for example, preconceived ideas about the jobs men and women should go into.

Economics could also be a factor, the researchers suggest, with boys under more pressure than girls to pick a career with higher financial reward, even if they're not particularly passionate about it.

Next for this particular avenue of research is testing the same kids over an extended number of years, and in regards to more complicated maths skills (such as those involving spatial processing and memory, for instance).

The team behind the study wants to see less of a bias in the way boys are pushed towards STEM fields more than girls – whether that's from teachers or parents. Kids can easily pick up on signals from the adults around them, which might be why women only account for around a fifth of STEM doctorates.

"Typical socialisation can exacerbate small differences between boys and girls that can snowball into how we treat them in science and math," says Cantlon.

"We need to be cognisant of these origins to ensure we aren't the ones causing the gender inequities."