As a child, I could not think of anything worse than being friends with a boy. And sadly it looks like plenty of men and women still feel that way. Sociologist Lisa Wade has written about her research for Salon, which shows that in the US, heterosexual men tend to have very few friends, and the relationships they have with other men provide less emotional support than their wives or girlfriends. This piece comes just a few days after an NSPCC study showing that young boys and girls struggle to maintain friendships because they're teased and pressured to turn a platonic relationship into a romantic or sexual one. It's no wonder boys struggle to make friends – just who are they supposed to be friends with?

Wade's research suggests the damage is done by the lingering idea that close friendships aren't masculine. Friendship is associated with intimacy and vulnerability; sharing feelings with, confiding in and supporting the people around you could suggest weakness. I don't believe men are naturally wired to be any less intimate and caring than women are. But if young boys grow up in a world where they're mocked for pursuing friendships with girls, and don't see enough examples of friendships between older men, it's going to cause huge problems for men and women later in life.

Without a network of friends, boys are going to grow up to feel confused, lonely and alienated. According to research from the charity Calm, suicide is now the biggest killer among young men in Britain, with a spokesperson for the charity citing "social isolation" as a major factor. If boys were explicitly encouraged to develop and invest in friendships, it could save lives. And if we tell them that it's important to make friends with girls as well as other boys, it could change feminism for ever.

I didn't identify myself as a feminist until I was almost 20, because it took me an embarrassingly long time to see, and truly believe that men and women are equal. The damage started at school: boys were disgusting, it was impossible to have one as a friend, unless they were your boyfriend. Gender stereotypes were rigidly enforced by both sides, from the games we played to the future career plans we discussed. I was even suspicious of my male cousins. They were boys, and as far as I was concerned that meant we had nothing in common and it wasn't worth having a conversation with them – they would only want to talk about football, or farting. When I was old enough to start dating, I started to reassess my horrible, narrow, stereotyped idea of men, and eventually matured enough to realise that we're all on the same team, and should be able to enjoy each others' company and benefit from other perspectives.

Many of my male friends say that as children they felt about girls the way I felt about boys. Luckily, they've matured into smart, sensitive feminists who believe in equality too. But we can't rely on luck to ensure everyone undergoes this transition. It's no wonder that patriarchal ideas prevail when many men grow up to see women as a sexual or strange other. If boys don't grow up knowing that girls can be just as funny, silly, clever and disgusting as they are, they will struggle to empathise with us. They might not understand why the pay gap and the proper division of domestic labour is a problem, because they won't have any evidence that women's concerns are everyone's concerns. If they're raised to believe that women exist only to fancy and go out with, they're never going to understand why the proliferation of pornography can be so dispiriting and dehumanising. I know some vocal male supporters of the No More Page 3 campaign, and they're not just speaking out on behalf of their mothers, sisters and daughters – they're angry because women are their good friends. You don't objectify your friends.

The Pink Stinks campaign is addressing the problems that arise when girls are pressured to play with overtly feminine toys. But we urgently need to talk about the way we gender kids' emotions too. Young boys are taught to fear feelings, because they are "girly", but they need to start sharing them – and start playing with girls.