When I was small, I was given a Little Housewife Set by my cousin Stan. I discarded the dustpan and brush and promptly whacked him over the head with the broom. The set, along with any notion of my developing domestic skills, was swiftly swept into the bin.

Toy manufacturers have always known that highlighting and exaggerating the variations between girls and boys is big business. Differentiate between the sexes and you can double your profits. Lego now also comes in female-friendly pink. That’s presumably so that young princesses can build their own palaces before snaring that prince with a few Cupid’s arrows.

Or they could use the heavy-duty option and hunt him down with a Hasbro Nerf Rebelle Heartbreaker bow-and-arrow blaster. Our heroines, it seems, are slowly changing, thanks to the likes of the Hunger Games series, and the toy industry is responding by marketing a more aggressive line of playthings - in suitably girly colours, of course.

The latest scientific research shows that, like their bodies, men and women’s brains are different but these differences are small. And the connections in the brain can change throughout life, in response to learning and experience. There is no such thing as “hard wiring” when it comes to brain connections. In fact, according to Anne Fausto-Sterling, professor of biology and gender studies at Brown University in the US, the word “hard-wired” should be expunged from people’s language. “If we were born hard-wired, then kids would be born walking and talking. Wiring develops - and by wiring, I mean interconnections in the brain,” she says in our cover feature.

That has huge implications for how we treat children. Boys will be boys, but only if we show them how. Reinforcing gender stereotypes is something we all do, consciously or unconsciously. There is no point lamenting boys’ aggression when we arm them with toy weapons and play rough and tumble from an early age. Equally, there is no point agonising over the dearth of girls taking up STEM (science, technology, engineering and maths) subjects if they have been discouraged from taking an interest in the world around them and encouraged only to wallow in a pink, fluffy marshmallow land. Children look for their cues from adults as they try to work out who they are and what is expected of them.

In school it’s not just about the way teachers relate to students: gender stereotyping can go the other way. One US teacher knows this only too well, having spent 12 years teaching as a man and another 13 as a woman. Jennifer Finney Boylan found that as a man she had to draw students out to start a discussion, but as a woman they couldn’t wait to jump in because they felt she created an environment in which it was safe to share feelings. “Is that really my stock-in-trade now that I’m female, the sharing of feelings instead of ideas?” she wrote in The New York Times.

Schools want all children to reach their full potential. Preconceptions about sex, whether conscious or unconscious, will prevent their doing so. The classroom must be a neutral environment and it is vital that teachers check their prejudices at the door. Or they might find, like my cousin Stan, that stereotypes sometimes find a way of hitting back.

ann.mroz@tes.co.uk