People tend to be surprised when they first hear what Matt Pinkett does for a living. “They assume I’m a bouncer, or perhaps a barman,” says Pinkett, 33, who shaves his head and has an East End accent. “What do they expect a head of English to look like – should I be wearing a tweed jacket with elbow patches?”

He certainly isn’t wearing that right now: he is in a sharp suit, shirt, braces. But it’s not just the appearance of teachers that Pinkett, who teaches at Kings college, Guildford, wants to challenge; it’s the bias that some have around their expectations of their male pupils, and what they can achieve. That’s the issue at the heart of Boys Don’t Try?, the book he has co-authored with fellow English teacher Mark Roberts; as its subtitle explains, it is all about “rethinking masculinity in schools”.

Boys’ underachievement permeates education; it’s not just a class issue, linked to deprivation, they say. Roberts, the assistant principal of Tavistock college in Devon, grew up in a working-class family of four boys in Yorkshire and is now the father of three young sons. He says he mistakenly thought, when he taught in an inner‑city comprehensive in Manchester, that boys’ underachievement was connected to deprivation.

Teachers don't like to admit they're human. There's a pressure on us to think of ourselves of saints

“I thought things would be different in Devon – but it’s not so different, and it’s not all to do with class. There’s also this anti-school mindset fuelled by stereotypical masculinity – like the stereotype that schoolwork is something girls ‘naturally’ do best,” he says.

Pinkett’s Damascene moment came a few years into his teaching career while discussing a poem with a female colleague. She said the way he interpreted it was down to the fact that, as a man, he thought about sex the whole time. “It was acceptable sexism, because it was directed at a man not a woman,” says Pinkett. “And it made me realise that, though girls and women undoubtedly come off worse as a result of sexist assumptions, boys and men are damaged by them, too.”

That damage is what he and Roberts (the two met on Twitter over shared concerns about masculinity) now seek to ameliorate. These mistaken expectations are what matter most, says Pinkett. “There’s a ‘boys will be boys’ attitude that plays into a narrative that says boys produce more testosterone, and that’s why they fight and punch, that’s why they don’t sit quietly in lessons, that’s why they’re harder to control, that’s why we have different expectations about what they can do.” But the hormone system is much more complex than such a binary reading reveals; and for every study that links bad behaviour and testosterone, there’s another, says Pinkett, that suggests it’s more about environment than biology. “The ‘men are from Mars, women are from Venus’ philosophy neglects two key facts: firstly, that there are more similarities than differences between the sexes, and, secondly, that our brains are plastic and changeable, especially during the early years.”

Facebook Twitter Pinterest ‘It’s about having high expectations for boys as well as for girls,’ says Mark Roberts, assistant principal of Tavistock college in Devon. Photograph: Alamy

The key to changing attitudes in schools, Pinkett believes, is for teachers to admit they are as prone to the same biases as everyone else. “Teachers don’t like to admit they’re human. There’s a pressure on us to think of ourselves as saints: to admit our fallibilities is to admit you’re human, yes – but who wants a robot for a teacher?” What teachers have to get past, he says, is the belief that if a boy doesn’t comply, doesn’t hand in homework or is misbehaving, that it’s because he’s male. “We need to stop ourselves: because maybe whatever is going on isn’t, after all, because he’s a boy. And it’s that realisation that can free pupils from stereotypes, and give them the chance to do what everyone wants, which is truly fulfil their potential.”

There’s a danger of treating boys differently and patronising them, says Roberts. “So, for example, you’ve got a boy you think doesn’t like reading, so you decide to pander to his love of football and give him a book about that to read. But in narrowing your expectations, you’re narrowing his. It’s the same with, for example, teaching boys about Shakespeare by concentrating on the sword fights or the fighting: it’s like we’re hoodwinking them into learning, and it doesn’t work. What we need is a big shift in ethos: too many teachers believe boys can do less, they don’t think boys can succeed as well as girls at school. I don’t think it’s about watering it down: it’s about having high expectations for boys as well as for girls.”

The content being taught is also relevant, and connected, of course, to everything else. “The English curriculum is unfairly and disproportionately dominated by men, and many of them are deplorable men like Macbeth and Dr Jekyll. And Dickens: a lot of his writing is unsavoury. So we need to challenge that in school, and we need to think about issues around sexist male behaviour and violence in the texts they’re reading.”

Pinkett and Roberts have pored over the statistics and, for Pinkett, there’s one that is far and away the most shocking; and that relates to sexist behaviour in British schools. “Around half of female students, and a third of male students, report having witnessed someone using sexist language,” he says. “And a third of girls have experienced unwanted sexual attention in school. It breaks my heart that’s how boys prove their masculinity – by using sexual language and bravado in which girls, and female teachers, become the victims.”

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In the book, he and Roberts push the idea of “tender masculinity”, which they counter not with “toxic masculinity”, a term they find unhelpful, but with “non-tender masculinity”, since that implies the absence of something better, rather than the presence of something poisonous.

The solution, says Pinkett, must be properly signposted policies, clearly displayed on school websites, that set out what is and isn’t acceptable. “We need the same specific, designated policies in this area as there are on, for example, racism and homophobia,” says Pinkett. “At the moment, 64% of teachers are unaware of any policy in their school on sexism. They’re feeling the effects of it, but they’re not seeing the steps being taken that would begin to eradicate it. And though it’s a complicated problem, and there’s a long road ahead, this is definitely the moment to start – for everyone’s sake.”

• To order a copy of Boys Don’t Try? by Matt Pinkett and Mark Roberts (Routledge, £16.99), go to guardianbookshop.com. Free UK p&p on all online orders over £15.