Britain has always had an uncomfortable relationship with sex education.
Teaching children about the timeless act of adults doing it to each other has always been sensitive. Even grown-ups struggle to avoid descending into juvenile ribaldry whenever sex is mentioned, so how are actual juveniles supposed to cope?
Professional teachers help, of course, but the sight of a middle-aged adult desperately trying to slip an excessively-lubricated condom on to a banana can only achieve so much.
Sex education - which at my school made it briefly fashionable for enlightened year sevens to use 'penis!' as a witty insult - remains fraught with awkwardness.
Here's how the British have coped with it over the last 100 years, in ten messy steps.
1920s-50s: Hygiene, plants and gonorrhoea
Children have been learning about sex for years, but after the First World War the British still hadn't decided it was necessary to actually put the topic in the classroom. Instead girls were provided with instructions on topics like "self-reverence, self-control and true modesty" - very medieval. The Second World War changed all this; the imminent collapse of civilization tended to break down social barriers, and sex education became more about avoiding syphilis, gonorrhoea and the like. By the 1950s, sex was in schools - but only in the context of what plants got up to with their anthers and their stamens. Girls, oddly, tended to get more teaching of biology than boys.
1960s - Time for birth control
In October 1963, the Family Planning Association made a big step. Its recommendation of a parliamentary bill to provide free advice for family planning under the NHS was a massive shift from what had come before. This, combined with the Abortion Act of 1968, helped pave the way for a change of attitudes. Yet the sexual revolution which engulfed Britain in the 1960s didn't start in Westminster; nor was it middle-aged MPs who were burning their bras, largely because none of them wore them. Parliament responded, passing the Abortion Act in 1968, another big social change for the country. It was perceived as being part of the problem, though: after it was enacted, unwanted teenage pregnancies still needed tackling.
1974 - Free condoms on the NHS
The prudes were shocked by what happened next. From 1974, the British government became responsible for providing contraception to anyone who walked into an NHS clinic, youth club or drop-in centre. The supply of free sex this suggested set the tone for the establishment's approach to sex among the young; a string of attempts throughout the 1970s and 1980s to lower the total number of teen pregnancies. They were, broadly, unsuccessful. More teenagers knew how to put on a condom, yes, but many more were bumping uglies.
1993 - Sex on the national curriculum
Fast-forward to the 1990s, and the first in a series of changes enacted by John Major's government, no less. The Education Act of 1993, responding to the Aids epidemic, required sex education to be provided "in such a manner as to encourage young people to have regard to moral considerations and the value of family life" across England and Wales. All state schools had to provide sex education in some way or another - including in primary schools, where the national curriculum covered the basic biology of sex. Individual schools got to pick whether they provided more than this.
1996 - Bundled up
Then came the Education Act of 1996, in which all the previous legislation was bundled together. Anatomy, puberty, biological aspects of reproduction, hormones, STIs were all confirmed as mandatory. School governors had to come up with detailed sex education policies.
2000 - Take it or leave it
After the Tory government had wrapped up its sex education policy, touchy-feely New Labour showed up - and decided even more was needed. In 2000 it passed the Learning And Skills Act, which broadened sex education. The importance of marriage was boosted. Young people were protected from inappropriate teaching on the basis of their religious and cultural background. Parents were given the right to withdraw their child from all or part of sex education outside the basics being covered in science lessons.
The kids didn't like it one bit. In February of 2000, a study from the University of Brighton found girls felt classes were focused too much on the mechanics of sex and contraception, not the emotions. Boys, too, felt they were being denied crucial details. Worst of all, they blamed legislation for preventing them getting access to the right information.
2008 - The internet takes over
Rather than learning about sex in classrooms, teenagers simply went online instead. In 2008 a sex education survey by YouGov found more than a third relied on sex advice from friends, the internet, magazines and pornography. They worried about the size and/or shape of their wobbly bits. Nearly three in ten said they needed more sex education in schools, but weren't getting it.
2012 - Prudishness endures
Somehow, the British couldn't get over their deep discomfort over showing sex to children. The Channel 4 sex education film Living And Growing, broadcast in 2012, proved a case in point. This was a programme for year fives (not five-year-olds). It featured an animated couple totally doing it. First he's on top. Then she is. "It's very exciting for them," the friendly-sounding female adult narrator says. "They do look happy, don't they?" a child's voice replies. It's cringeworthy - or is it?
2013 - Nothing changes
By 2013 it had become clear that the present system simply wasn't working. Ofsted published a report, Not Yet Good Enough, echoing the findings of that University of Brighton study from 2000. In over a third of schools, there was again too much focus on the "mechanics" of sex and not enough on the emotions surrounding it. There was "too little" focus on "relationships, sexuality, the influence of pornography on students' understanding of healthy sexual relationships, dealing with emotions and staying safe".
Labour tried to change all this last year, with a proposal to get more teaching on the importance of sexual consent as part of the national curriculum. It was rejected in the Commons and the Lords.
2014 - Lib Dems propose sex ed for all
And now, finally, one of the two coalition parties which blocked Labour's proposal appears to have had a change of heart. The Liberal Democrats have announced they want all seven-year-olds in state-funded schools to receive sex education. Their attitude is to bunch sex education in with other essential 'life skills' like balancing a budget or voting for the first time. They blame the Tories for being completely uninterested in changing the status quo.
In government, the Conservatives' focus has been on looking for technological ways of clamping down on young people's access to pornography. Yet the internet, like the sexual revolution which began half a century ago, is changing the social context in which the politicians operate. Back then, Westminster responded with the Abortion Act and the provision of free contraception. Today, the political class has not yet been prepared to respond in a similarly bold fashion. That may change after the next general election. But for now, this is a tale of sexual education frustration which doesn't have a very happy ending.