"'Slutty, slaggy' girls need David Cameron to sort sex education. Fast." Thus reads the Telegraph’s headline to a serious piece by Green party MP Caroline Lucas, calling for education on sex and relationships to be made compulsory in schools.

You could be forgiven for thinking that the problem is that girls really are "sluts" and "slags", in need of a good talking-to from Dave. It’s actually nothing of the sort. One in three girls have experienced unwanted sexual touching at school, while 71 per cent hear the terms "slut" or "slag" used to describe female students on a weekly basis. The problem, in other words, is sexism, although no one, not even Lucas herself, will say so.

Instead, Lucas argues that, “each and every child in this country should have an entitlement to excellent sex and relationship education”. With that I am in full agreement. The Education Secretary Nicky Morgan has made similar arguments, saying that schools need to put, “high-quality PSHE at the heart of their curriculum.”

Both Lucas and Morgan identify sexting and online pornography as a cause of significant problems in schools. Nonetheless, while they have little difficulty in identifying most victims of harassment as female, perpetrators are described in gender-neutral terms. At no point does anyone use the words “male sexual entitlement.”

I will use those words, however. I am a mother of sons and the thought of them growing up within a culture of rampant male sexual entitlement terrifies me. Right now they are six and seven – still innocent, still able to see their female peers as fellow humans – but as adolescence approaches, I fear that a deluge of misogyny will engulf them as they encounter the adult world and so-called “normal” attitudes to sex.

I am very much in favour of them being granted access to as much accurate, open-minded sex education as possible. Nonetheless, I doubt such teaching will ever be effective as long as we are in denial about the real problem: the widespread, culturally sanctioned dehumanisation of women as the price for male sexual gratification.

There is no point in explaining consent to boys, as though it is some peculiarly complex social exchange. It isn’t. What confuses them is the fact that our pornified, misogynist culture treats female bodies as soulless objects. They witness this everywhere: on TV, in the news, online, on the streets, in the words of their peers and elders.

They can sit in a classroom and be informed about the rights and wrongs of it. They can be encouraged to think, in abstract terms, about the Woman as Person. But that is not how they encounter her in the media, nor in the minds of fellow men. Deep down, they know that their “right” to access hardcore pornography and purchase female flesh is inviolable. The Woman as Person narrative is subordinate to the one telling them that the ultimate human right is a “real” man’s right to fuck.

Among many self-styled progressives there is an assumption that the same moral principles that justify compulsory sex education also justify a non-critical attitude towards porn and the sex trade. The “my enemy’s enemy is my friend” fallacy convinces them that anything which annoys some mythical US-style religious Right has to be a good thing.

Hence student unions and fem socs across the land will organise consent classes for male students while condemning all criticism of the sex industry as “whorephobic.” The inconsistency escapes them. They haven’t noticed that, as Dworkin pointed out thirty years ago, male-dominated right-wing moralists are no more bothered by the exploitation of women’s bodies than left-wing sexual libertarians. They’d much rather put their energy into policing women’s access to abortion than men’s access to torture porn, just as left-wing warriors for sexual justice would rather spend their time attacking anti-porn feminists instead of asking how, and why, men across the world learn to treat women as objects into which you insert other objects, again and again, perhaps until they die.

This week a court heard how Majella Lynch died after a severe sexual assault left a full 400ml shampoo bottle in her stomach cavity. The man accused of the attack is described by the prosecutor as having “an interest in violent sexual activity” and having viewed “extreme violent porn.” Meanwhile in Ireland Magnus Meyer Hustveit received a suspended sentence for repeatedly raping his ex-girlfriend while she was unconscious. In a pleading letter to his ex, he explained that “I didn’t want to hurt you, I just wanted to come. I used the fact that I wasn’t allowed to watch porn or masturbate as an excuse.”

The judge’s decision not to imprison Hustveit, plus reader comments from Irish news sites, suggest that literally using a woman as an inanimate hole in which to ejaculate is considered an easy mistake to make. Earlier this year the killer of Cindy Gladue, an aboriginal sex worker in Canada, was acquitted after convincing a jury that Gladue consented to sex so rough she bled to death with an 11-centimetre wound in her vagina. Evidence from Bradley Barton’s laptop, showing that he visited pornography sites featuring extreme penetration and torture, had been ruled inadmissible at the trial. Unfortunately, Gladue was no longer around to say what happened; the only part of her that appeared in court was her pelvis, to allow jurors to examine the gaping wound.

Where do these men come from? Why do we define what they do as one-offs rather than the hate crimes they are? Why do we defend the media that reflects their image of women back to them? Why do we expose our sons to it then think we can mop up all the damage with the odd PSHE session on a sleepy Friday afternoon?

It is easy to start teaching your sons about physical boundaries and consent. Even when they are very young you will find instances where it is appropriate to tell them to stop if another child is not responding to their desired form of play (“no, you can’t do that now, not even if he was happy for you to do it five minutes ago!”).

But then they get older and learn that, for some magic, inexplicable reason, male-initiated sexual contact with women is the exception to this rule. You can’t attack that, otherwise it’s “shaming”. For some reason, whatever arouses heterosexual men exists on another moral plane. It’s not enough to tell them that their hidden desires do not make them bad people. Such desires must be endorsed, enacted and filmed for redistribution.

Fantasies of kicking puppies to death? Bad. Fantasies of ramming butcher knives into vaginas? Well, whatever turns him on. You don’t want your son to grow up feeling ashamed of his personal preferences.

What will my sons learn from a few hours taken out of a whole lifetime of being told that women are, if and when you want them to be, no more than holes for fucking? I have a hard enough time telling them they’re allowed to like pink.

People in positions of supposed authority – parents, guardians, teachers – can’t override every single cultural message bombarding their charges the moment they are out of sight. They are growing up in a world in which most adult males consider hardcore pornography and the sex trade perfectly acceptable, and most women, even those who disagree, know to keep their mouths firmly shut (unless they’re being ordered to open wide). A world in which consent is cool but girls are worthless, so the only option is to fake enthusiasm. A world in which newspapers create misleading, titillating headlines about "slutty, slaggy" girls rather than take the sexual abuse and harassment they experience at school seriously.

People who are unwilling to challenge such a world can say what they like about valuing consent. Their words are hollow. It seems no one is afraid to talk about sex, but sexism remains taboo.