The really frustrating thing about Nadine Dorries is that, just when you think she might have gone away for a while, she comes back spouting more evidence-free drivel about sex. Not the abortion counselling adjournment debate – that was organised by the Labour MP Gavin Shuker – but her other pet issue, the Bill on compulsory abstinence education for girls, which is due to get its second reading in the House of Commons on 20th January.

Dorries first introduced this bill in May 2011, when nobody really expected it to be taken seriously. It proposes that lessons on sexual abstinence should become compulsory for all girls aged 13-16 in English state schools. The only elements of Sex and Relationships Education (SRE) that are currently mandatory are the scientific explanation of where babies come from, and, in free schools and academies, a duty for teachers to promote marriage. Individual schools have the freedom to decide what else should be taught, and in the face of tabloid-inspired moral outrage about SRE encouraging young people to have sex and driving up the number of teenage pregnancies (despite the fact that the number of teenage pregnancies in the UK is actually falling), there is a risk that more schools could shy away from providing young people with practical, factual information about sex.

The same moral outrage has already influenced policy in the USA, where the rise in abstinence-based sex education during the years of George W Bush’s presidency corresponded with an increase in pregnancies and STIs among teenagers – proving conclusively that it doesn’t work. The approach that Dorries suggests isn’t exactly the same, as it could in theory be used in addition to lessons about contraception instead of replacing them entirely, but the fact that it is aimed at girls means that there are certain similarities with some of the well-known American abstinence movements, such as purity balls. Defenders of abstinence education claim that this is because boys don’t have to live with the consequences of a teenage pregnancy, but it is rooted in older traditions that value women’s virginity over that of men. Virginity used to be one of the major indicators of a woman’s worth in the marriage market, and because it was signified by a physical state – having an intact hymen – it could be proven, either by physical examination or through traditions like displaying blood-stained bedsheets the morning after a wedding. Even though the hymen has become redundant as a test of virginity in many parts of the world (they tend to be broken during exercise or by tampons before a woman’s first sexual partner shows up), sexual experience is still more stigmatised for women than for men.

Leaving boys out of abstinence education isn’t the same as encouraging them to have sex, but it perpetuates the idea that women should be sexual gatekeepers. By saying that it is a woman’s responsibility to say no to sex, Dorries implies that men (abstinence education tends to only be concerned with sex between a man and a woman) can’t be trusted to make the right decision on whether or not to have sex, so women have to do it for them. This is insulting to everyone involved, implying that men can’t – or shouldn’t be expected to – control their own sexual behaviour, and it’s part of the same logic that blames women for “inviting” rape.

In stressing the importance of young women saying no to sex, Dorries is also showing ignorance of young women’s experiences. Consent is a far more complex issue than pro-abstinence campaigners would have us believe, and sometimes women agree to sex that we don’t want. Many young women are already saying no, but some men won’t accept that answer, and will continue to press the issue. The “no” that might be have been relatively easy the first few times becomes increasingly difficult to maintain under repeated pressure, and eventually a reluctant “yes” is granted.

This might sound like an argument for abstinence education – if girls find it difficult to say no, then shouldn’t we help them? Yes, but the problem here is that this isn’t just about sex, it’s about society’s expectations for masculine and feminine behaviour. We expect men to pursue women; we call it seduction, and it’s supposed to be sexy, but sometimes it’s used as an excuse for coercion. We teach men that they need to get consent for sex, so most will wait for a “yes” before they proceed, but some only learn the importance of the word, not the sentiment behind it, so it becomes acceptable to badger a woman until she verbally agrees, regardless of whether she really wants to have sex.

While men are encouraged to be persuasive and forceful, women are taught from an early age that they aren’t supposed to say no – not necessarily to sex, but in general. We teach girls to be considerate, obliging, and to put others before themselves. These lessons aren’t consciously intended for the bedroom, but they’re not something we can easily leave at the door. The “no” that Dorries expects from teenage girls is a difficult answer to give, because it’s at odds with how they are encourage to behave in all other aspects of their lives. Abstinence lessons won’t undo the effects of living in a culture which discourages women from being assertive, and neither will Dorries’ proposals teach men to listen and accept what a woman says when she does assert herself.

Abstinence is a loaded term, and it’s very black and white, which means that it isn’t particularly useful for discussing how and why we make decisions about sex. Sex doesn’t happen in a vacuum – not for teenagers, and not for adults either – so putting it in a box marked “just say no” isn’t going to work.