No means no ...

Akin says he "misspoke" when he issued a garbled soundbite which had all the hallmarks of fundamentalist Christianity's more wacko beliefs. He used the baffling phrase "legitimate rape" and then employed pseudo-science to suggest that a woman who had been raped probably wouldn't become pregnant because "the female body has ways to try to shut that whole thing down".

Those of his compatriots with access to column inches have already made their thoughts on his comments abundantly clear. Female voters in Akin's home state of Missouri may do the same thing at the ballot box. Galloway, ever the controversialist, stepped into a case even he should probably have tiptoed around: that of Julian Assange and the sexual assault allegations facing him.

The 41-year-old WikiLeaks founder is currently sheltering in the Ecuadorian embassy in London where he is fighting attempts to extradite him to Sweden to be questioned over allegations made against him there by two women. There are four allegations. Each occurred during or after apparently consensual sex and have been translated from Swedish legalese into English phrases such as "unlawful coercion" and "sexual molestation". Among other things they involve the non-use of condoms (against the express wishes of at least one of the women) and that Assange had unprotected sex with one woman, known as Miss W, while she was asleep. Assange contests the allegations.

The incident has sparked a debate about what does and doesn't constitute consent between sexual partners, what we mean when we talk about rape, and about how comments such as Galloway's may highlight a troubling divide in how some men and women view the subject.

So what exactly did the Honourable Member for Bradford West say? "Not everybody needs to be asked prior to each insertion," Galloway began. "Some people believe that when you go to bed with somebody, take off your clothes, and have sex with them and then fall asleep, you're already in the sex game with them."

To Galloway's mind such a scenario is "really sordid", "bad manners" and "bad sexual etiquette". But, he added, "it is not rape or you bankrupt the term rape of all meaning".

In legal terms, the issue of consent is clear. The Sexual Offences (Scotland) Act 2009 says that a man has committed rape if he has sex with a woman without her consent. The Act adds that he is also guilty of rape if this happens without "any reasonable belief" that the woman consents. But could the fact of being naked in bed with a woman, having already had consensual sex with her, give a man that reasonable belief?

Predictably, Galloway's intervention has caused outrage. "Sexual consent is not football; you can't buy a season ticket," countered Galloway's fellow MP Louise Mensch. For her, as for most women, the issue is simple. "Rape is when a woman does not consent. Because she is, for example, asleep and unconscious."

Journalist Cristina Odone attacked what she sees as the inherent misogyny of both the political left and right while feminist writer and domestic violence campaigner Julie Bindel wrote about the widespread scourge of "rape denial" among men, and the "false division" of rape into a series of crimes with varying levels of seriousness. Echoing Mensch, Bindel added: "It used to be enshrined in law that once a woman had consented to sex once – such as with her husband – he could stick it in whenever he felt like it. Today, it is not a legal right to have sex with a person simply because you have been there before."

But while there may be unanimity among women on the subject, opinions vary among men. No man will freely admit that they hold the views described by Bindel, but turn to the chat rooms and internet forums and it is clear that there is some support for George Galloway's views. Here's Jay58, replying on Yahoo! Answers to the question, "Do you agree with George Galloway's definition of rape?": "What a man does in the situation he [Galloway] described can be criticised in that he did wrong. But I go along with him in believing that calling such actions 'rape' devalues the concept."

The "concept" of rape, as far as some men are concerned, is one in which a woman is forced to have sex, perhaps at gun or knifepoint, by a stranger. This flies in the face of the facts – most women are raped by men they know – but it presents a scenario in which everyone can agree there is only black and white. A few men are callous, violent serial rapists but most men know that the crime of rape as described there is not one they would commit.

Shades of grey do exist, however. Imagine a Friday night, post-pub scenario involving two young people who are drunk and engaging in a form of intimacy which is consensual in the sense that clothes have been shed and a sexual coupling of some sort is expected. What man hasn't found himself in that situation? And if the word "no" is never uttered, if there is no struggle, no violence, few man would imagine they might find themselves facing a rape charge afterwards. But it could happen.

"It is a messy area that I'm not surprised worries men and makes them wonder what kind of seemingly consensual sexual act that has occurred without explicit verbal consent, might constitute rape," says Christina Wellor, sex and relationships columnist with GQ.com.

"But essentially, a human being understands the disapproval and unwillingness of another. A man also has the ability to know if a woman is aroused. If penetration is difficult and her body language is negative, this should be seen as a red light.

"The grey area really develops when women express a desire to be sexually dominated. Some even harbour and want to act out rape fantasies, albeit in an agreed, controlled situation. At what point does a man recognise that stop really means stop and how should the woman remain in control when he gets carried away?"

So in a summer when erotic S&M novel Fifty Shades Of Grey has proved a blockbuster hit with female readers, could men be forgiven for feeling they are getting mixed messages about the issue of consent?

And what happens if a woman appears to say nothing at all in bed? Defending himself in May against a charge of raping a 21-year-old woman in his bedroom, 29-year-old Brett Griffin said his accuser had moaned and groaned as he massaged her, had shown no resistance and that he had taken this as consent to penetrative sex. She, on the other hand, said she woke up to find him on top of her. In a unanimous decision at Reading Crown Court, Griffin was sentenced to five years for rape and placed on the sex offender's register for life.

Just last week, meanwhile, 27-year-old Ugandan Rogers Mutebi was jailed for five years in Edinburgh for continuing to have sex with a 24-year-old woman when she changed her mind after initially consenting. The case made legal history of a sort: it is the first prosecution for rape where consent was withdrawn.

But what might make someone who doesn't consider himself a rapist commit the crime and how easy could it be for a man to find himself in a situation where a line is crossed? The US-based social news website Reddit allows users to upload their own content and functions as a massive bulletin board. It covers every subject imaginable – including, last month, the question of whether any of its users had committed a sexual assault, what their motivations were and whether they regretted it. The truthfulness of the confessions it elicited can't be verified, but given the cloak of online anonymity bulletin boards confer, there's little reason to suppose the majority aren't genuine.

One man, who described himself as handsome and popular, said he had raped a number of women at college using a mixture of coercion and force when they were in his apartment after dates. "They didn't want it to happen, but they couldn't do anything about it," he wrote. "Most girls don't say no either. They think you're a good guy, and should pick up on the hints, they don't want to have to say 'no' and admit to themselves what's happening."

Another poster simply wrote: "Got drunk. Ripped a girls [sic] shirt. No longer drink. Not quite rape, but it scares the crap out of me to think I'm capable of even that."

Some posters evince what Julie Bindel would call "rape denial", some are contrite, a few are not, others are clearly damaged by what they did. But it illustrates what we should already know: that the rapist usually isn't an armed stranger in a black balaclava. He's a colleague, a friend, a fellow student. It also tells us that the catalogue of verbal and non-verbal transactions which lead up to people having sex are complex and subtle and that untangling them in the aftermath of an alleged sex crime can be equally difficult.

"Not all sexual encounters between couples even involve verbal communication," says Wellor. "Most couples have had a semi-conscious, midnight fumble that culminates in sex. Just because the woman hasn't verbally expressed her approval, doesn't mean she can later accuse him of rape."

That said, the direction of travel is constant and unwavering where education about consent to sex is concerned, particularly between relative strangers. You ask first and no means no. Against this background, however, men's sexual habits, proclivities, attitudes and even their sexual role models are changing – and not for the better. In her book Pornland: How Porn Has Hijacked Our Sexuality, British-born author Gail Dines argues that the prevalence of pornography is having a detrimental effect on those men who regularly view it and is affecting what they expect in the bedroom. "The more porn images filter into mainstream culture, the more girls and women are stripped of full human status and reduced to sex objects," Dines said. A generation of teenage boys, meanwhile, are viewing pornography which will have "a profound influence on their sexuality, behaviour and attitudes towards women". As a result, she sees them growing into men who are "bewildered, even angry, when real women don't want or enjoy porn sex".

So what is "porn sex"? It is the thing that makes increasing numbers of young men think sexual encounters should be condom-free, for instance, and include some (or all) of the various acts which are leitmotifs of almost every porn scene ever staged. To the feminist eye, these are violent images and one in particular – known in the porn industry as the "money shot" – is particularly indicative of men's desire to besmirch and mark women.

Scholarly opinion is divided on whether a causal link exists between sexual violence and the viewing of pornography. But within the feminist critique it is easy to construct a world in which more men have less respect for their sexual partners. In that same world it is safe to assume the issue of consent has a decreasing amount of purchase too.

Writing recently in the Daily Mail, former Loaded editor Martin Daubney issued a mea culpa for the years in which he peddled soft porn in the notorious lads' magazine. Now a father, he echoed Dines's concern for young men growing up with easy access to hardcore pornography but lacking the maturity to understand that what they see on screen isn't necessarily what they are going to encounter in the bedroom.

"The next generation of young men are becoming so desensitised, I genuinely fear we're storing up an emotional time-bomb," he wrote. "In porn, women cry, 'yes, yes, yes!' but in real life, they often say, 'no'. Not all men have the intelligence or moral fortitude to understand they cannot take what they want."

ChildLine founder Esther Rantzen is now adding her voice. "For many teenagers, their understanding of what is normal is becoming so warped that they are mimicking behaviour which is aggressive, harmful and dangerous," she said yesterday as she launched a campaign to block children's access to web porn.

Last week, George Galloway and Todd Akin became the latest politicians to cause controversy with comments about rape; Julie Bindel, Louise Mensch and Cristina Odone all raised their voices in dismay and dispute; and around the country some men charged with rape were sentenced and some acquitted. The law is clear but when applied to real life it can become less so.

The talk of rape continues and will probably never stop – and as for the "sex game" all men are in to a greater or lesser degree, it is only going to get harder to play if no-one can agree on the rules.